Algebra 1 just teaches you how to solve word problems by assigning x as the unknown. Algebra 2 is a little bit tougher. Many times you have to deal with more than 1 variable. So here goes......
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The sum of two numbers is 161. two times the smaller number plus forty-seven is the larger number. what are the numbers?
Let
x = the smaller number
Here, never bother to solve for what to assign the larger number.
Let
y = the larger number
The sum of 2 numbers is 161
x + y = 161
two times the smaller number plus forty-seven is the larger number.
2 · x + 47 = y
Now we have the equations
x + y = 161
2x + 47 = y
How do you solve 2 equations with 2 variables? There are many methods of solving. But in this case I will show to you the quickest and most effective ways to answer.
We are given
2x + 47 = y
then,
y = 2x + 47
But
x + y = 161, so substitute y:
x + (2x + 47) = 161
x + 2x + 47 = 161
x + 2x = 161 - 47
3x = 114
x = 114/3
x = 38
We now have the value of x. To solve for y, substitute x = 38 to
y = 2x + 47
y = 2(38) + 47
y = 76 + 47
y = 123
Therefore,
the numbers are 38 and 123.
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The sum of a number and a number is that is two-thirds of the first number is fifty. what are the numbers?
Let
x = the first number
y = the number that is two-thirds of the first number
Thus,
To get the equations, analyze every part of the question.
Since their sum is 50,
x + y = 50
Since y is 2/3's x,
y = 2/3 x
We now have the equations
x + y = 50
y = 2/3 x
Now you can simply substitute y into the first equation
x + y = 50
x + (2/3 x) = 50
x + 2/3 x = 50
Multiply 3 to both sides
3x + 2x = 150
5x = 150
x = 150/3
x = 30
To solve for the other number, subs. x = 30 into
y = 2/3 x
y = 2/3 (30)
y = 20
Therefore, the numbers are 30 and 20.
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The sum of two numbers is 2173.7 their difference is 884.1 what are the numbers?
Let
x and y = the numbers
The question tells us that
x + y = 2173.7 and
x - y = 884.1
Here, if you add the two equations vertically, it yields
2x + 0 = 3057.8
2x = 3057.8
x = 3057.8/2
x = 1528.9
To solve for y,
x + y = 2173.7
y = 2173.7 - x
y = 2173.7 - 1528.9
y = 644.8
Therefore, the numbers are 1528.9 and 644.8.
Hope this helps^_^
^_^
2006-08-25 22:49:03
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answer #1
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answered by kevin! 5
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1)
x is the small number
y is the larger number
the sum of two numbers is 161 -----> x + y = 161
two times the smaller number plus forty-seven is the larger number -----> 2x + 47 = y
Rewrite as : 2x - y = -47
Write them side by side and add the equations together:
x + y = 161
2x - y = -47
(x + 2x ) + (y - y) = (161 - 47)
3x + 0 = 114
3x = 114
x = 114/3
x = 38
x + y = 161 ---> 38 + y = 161
y = 123
2)
the sum of a number and a number is that is two-thirds of the first number is fifty
x is first number
y is second number
y = (2/3)x
x + y = 50
Try from there...
3)
the sum of two numbers is 2173.7
x + y = 2173.7
difference is 884.1
x - y = 884.1
2006-08-25 15:43:47
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answer #2
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answered by Anonymous
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the sum of two numbers is 161. two times the smaller number plus forty-seven is the larger number. what are the numbers???
x+y=161 2x+47=y
x+(2x+47)=161
3x+47=161
3x=114
x=38
2(38)+47=y
123=y
the sum of a number and a number is that is two-thirds of the first number is fifty. what are the numbers?
x+(2/3)x=50
1(1/3)x=50
x=30 the other number is 20
the sum of two numbers is 2173.7 their difference is 884.1 what are the numbers?
x+y=2173.7 x-y=884.1
x=884.1+y
(884.1+y)+y=2173.7
884.1+2y=2173.7
2y=1289.6
y=644.8 x=884.1+644.8
x=1528.9
2006-08-25 10:19:18
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answer #3
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answered by bretttwarwick 3
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The first one:
x+y=161
2x+47=y
This forms a system of equations. Just plug the second equation into the first one:
x+2x+47=161
and solve:
3x+47=161
3x=114
x=38
Go back to the first equation:
38+y=161
y=123
Number 2
Okay, this one doesn't make any sense to me.
Number 3:
x+y=2173.7
x-y=884.1
are the two equations that make up a system.
Change the second equation to x=884.1+y by adding y to both sides of the equation.
Then plug it into the first equation:
884.1+y+y=2173.7
884.1+2y=2173.7
2y=1289.6
y=644.8
So x=1528.9
2006-08-25 10:12:40
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answer #4
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answered by quepie 6
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x + y = 161
2x + 47 = y
substitute
x + (2x + 47) = 161
3x + 47 = 161
3x = 114
x = 38
therefore
y = 123
x + (2/3x) = 50
5/3 x = 50
x = 30
therefore
y = 20
x + y = 2173.7
x - y = 884.1
add...
2x = 3057.8
x = 1528.9
therefore
y = 644.8
2006-08-25 10:13:10
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answer #5
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answered by Gemelli2 5
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x+y=161 2x+47=y
x+(2x+47)=161
3x+47=161
3x=114
x=38
2(38)+47=y
123=y
x+(2/3)x=50
1(1/3)x=50
x=30 the other number is 20
x+y=2173.7 x-y=884.1
x=884.1+y
(884.1+y)+y=2173.7
884.1+2y=2173.7
2y=1289.6
y=644.8 x=884.1+644.8
x=1528.9
2006-08-25 11:11:45
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answer #6
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answered by sonicwingmode 2
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this is the equation to the first
x+y=161
2x+47=y
just solve the system
2006-08-25 10:05:52
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answer #7
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answered by crazed1511 1
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well....since evry1 else has done it me doing it is really pointless. Just think of IS as = and SUM as + and OF as x. its really not too hard.
2006-08-25 10:32:30
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answer #8
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answered by devil 2
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Do Your homework , by your own self ...
2006-08-25 10:56:28
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answer #9
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answered by Ayman 3
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