how do you solve 5x+2y=30 x-4y=17?

Answer 1

5x + 2y = 30- - - - -Equation 1
x - 4y = 17- - - -- --Equation 2
- - - - - - - - -
Substitute Method Equation 2

x - 4y = 17

x - 4y + 4y = 17 + 4y

x = 17 + 4y

Insert the x value into equation 1

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5x + 2y = 30

5(17 + 4y) + 2y = 30

85 + 20Y + 2y = 30

85 + 22y = 30

85 + 22y - 85 = 30 - 85

22y = - 55

22y/22 = - 55/22

y = - 2 11/22

y = - 2 1/2

y = - 2.5

The answer is y = - 2.5

Insert the y value into equation 2

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x - 4y = 17

x - 4(- 2.5) = 17

x - ( -10) = 17

x + 10 = 17

x + 10 - 10 = 17 - 10

x = 7

The answer is x = 7

Insert the x value into equation 2

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Check for equation 2

x - 4y = 17

7 - 4(- 2.5) = 17

7 - (- 10) = 17

7 + 10 = 17

17 = 17

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Check for equation 1

5x + 2y = 30

5(7) + 2(- 2.5) = 30

35 + (-5) = 30

35 - 5 = 30

30 = 30

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The solution set { 7. - 2.5 }

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Answer 2

This is called a system of equations. All that is needed to solve a system of equations is a matching number of equations and variables. In this instance, we have two variables (x and y) and two equations, so lets solve it!

There are several methods of solving systems of equations, several of which I'm sure you have learned. In this case I would take the following approach:

Given: 5x+2y = 30, x-4y = 17

Step 1: Multiply 1st equation by 2:

2(5x+2y = 30) --> 10x+4y=60

Step 2: Add equations:

10x + 4y = 60
+ x - 4y = 17
____________
11x = 77

Step 3: Isolate x by dividing by 11 on both sides:

11x/11 = 77/11
x = 7

Step 4: Solve for y by plugging in x = 7 to 2nd equation:

7 - 4y = 17
-4y = 10
y = -2.5

Step 5: Check Answers by plugging into either equation:

5x + 2y = 30, where x= 7 and y = -2.5
5(7) + 2(-2.5) = 30 ?
35 - 5 = 30
30 = 30 !

We have therefore solved this system of equations. You can use a similar method to solve most systems but every set of equations is different, and might require slightly different processes.

MATH IS FUN!!!!!!!!! HAHAHAHAHAAHA!!!!!!

Answer 3

Put the calculator in a drawer so you will have it when you NEED it!
5x + 2y = 30
x - 4y = 17
Substitution looks pretty OK: From the 2nd equation,
x = 4y + 17
Substituting into the 1st equation,
5(4y + 17) + 2y = 30
20y + 85 + 2y = 30
22y = -55
y = -5/2
x = 4(-5/2) + 17
x = -10 + 17
x = 7

Check:
5(7) + 2(-5/2) =? 30
35 - 5 = 30

Answer 4

This is like an addition problem

5x+2y=30
x-4y =17

First you want to make the bottom x term the same as the top x term so multiply through by 5

5x+2y=30
5x-20y=85

No you want the x term to cancel out so you can solve for y so multiply the botton by -1

5x+2y=30
-5x+20y=-85


So now u get 22y=-55....and divide by 22 you should get a y= -2.5

Now plug in the -2.5 into either the top or bottom and solve for x

5x+2(-2.5)=30

and x=7

Answer 5

So you want to solve the system of equations:

5x + 2y = 30
x - 4y = 17

I'm going to multiply the second equation by 5, because I want there to be a 5x (since the equation above has a 5x ... more details soon).

5x + 2y = 30
5x - 20y = 85

Now, what we're going to do is SUBTRACT the equations.

(5x + 2y) - (5x - 20y) = 30 - 85
22y = -55
y = -55/22 = -5/2

To solve for x, all you have to do is plug in your newly solved y into one of the equations. Let's choose x - 4y = 17
Then
x - 4(-5/2) = 17
x + 10 = 17
x = 7

Therefore, x = 7 and y = -5/2

Answer 6

um...just solve one equation well without the numbers u need i guess:
okay the way will be like this:
x-4y=17
x=4y+17 got it i subtact 4y to the other side
now just subsitute to the other equation
5(4y+17)+2y=30
now just solve it and find y
20y+85+2y=30
22y=55
then the answer should be y=55/22=2.5
i dont know y
and for the x just subsitute the y in the other equation not the same equation that i showed u that i solve for y
and then ur answer should be x=27

Answer 7

I) (5x + 2y = 30 (.2)
II) (x - 4y = 17
Addition:
(I) 10x + 4y +(II) x - 4y = 60 + 17
11x = 77
x = 77 : 11
x = 7

x - 4y = 17
7 - 4y = 17
-4y = 17 -7
y = 10 : -4
y = -2,5
Answering: {(7; -2,5)}
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Answer 8

5x+2y=30
5x=30-2y
x=(30-2y)/5
Now, substituting the x value into the next equation:
(30-2y)/5-(4y)=17
(30-2y-20y)/5=17
30-2y-20y=85
Combining like terms:
30-22y=85
-22y=55 or 22y=-55
y=-55/22 or -5/2

I do not know if this is what you want or not. Hope so

Answer 9

5x+2y =30 (A ) multiply second equation by 5 x -20y =- 85 (B)

Substract B from A

you have 22 y = 115

y =115/22 =5.23

replace by its value in (A)

5x +230/22 =30 x=3.9

Answer 10

5x+2y=30 & x-4y=17
x-4y=17
x=17+4y
now put x=17+4y in 5x+2y=17
5(17+4y)+2y=17
or, 85+20y+2y=17
or, 22y=17-85
or, 22y= -68
or, y= -68/22=-34/11
now x=17+4y
or, x=17+4(-34/11)=17-168/11=(187-168)/11=19/11
So x=-34/11 and y= 19/11 solved.