2006-09-23 00:56:08 · 7 answers · asked by double B 2 in Science & Mathematics ➔ Mathematics
You mean 5b -6a=8?
2a+5b=44
5b -6a=8
Use subtraction:
2a+5b=44
- (5b -6a=8)
2a+5b=44
-5b +6a= -8
8a=36
a=9/2
Substitute a=9/2 to ant of the equations:
2a+5b=44
9+5b=44
5b=35
b=7
Ans: a=9/2, b=7
2006-09-23 01:02:08 · answer #1 · answered by Lin 2 · 0⤊ 0⤋
2a + 5b = 44
-6a + 5b = 8
To solve by elimination you must make one of your variables cancellable in the system. I'd do it like this:
-(-6a + 5b = 8)
6a - 5b = -8
So now my system becomes:
2a + 5b = 44
6a - 5b = -8
By eliminating the 5b from the system, you can find the value of a:
8a = 36
a = 4.5
Now solve for b:
2a + 5b = 44
2(4.5) + 5b = 44
9 + 5b = 44
5b = 44 - 9
5b = 35
b = 7
Test your answers on the second equation:
5b - 6a = 8
5(7) - 6(4.5) = 8
35 - 27 = 8
8 = 8
Yes, the solution is correct: (4.5,7). And now you know how to solve a system of equations by elimination!
2006-09-23 05:48:18 · answer #2 · answered by ronw 4 · 0⤊ 0⤋
2a + 5b = 44 - - - - equation 1
-6a + 5b + 8 = 0- - --equation 2
-6a + 5b + 8 - 8 = 0 - 8
Subtracting - 8 from both sides of the equation 2
-1(-6a + 5b = - 8
Multiplying - 1 on equation 2
6a - 5b = 8
- - - - - - - - - - - - - - - - - -
Elimination of b
2a + 5b = 44
6a - 5b = 8
8a = 52
8a/8 = 52/8
Dividing both sides of the equation by 8
a = 52/8
a = 6.5
The solution set is { 6.5 }
Insert the a value into equation 1
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Solving for b
2a + 5b = 44
2(6.5) + 5b = 44
13 + 5b = 44
13 + 5b - 13 = 44 - 13
Subtracting - 13 from both sides of the equation
5b = 31
5b/5 = 31/5
Dividing both sides of the equation by 5
b = 6.2
The solution set is { 6.2 }
Insert the b value into equation 1
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Check
2a + 5b = 44
2(6.5) + 5(6.2) = 44
13 + 31 = 44
44 + 44
- - - - - - - - - - - - - - - -
- 6a + 5b = -8
- 6(6.5) + 5(6.2) = -8
- 39 + 31 = - 8
-8 = - 8
- - - - - - - - - - - - - - - - - - - - - - - - - - - -- - -- -
The solution set is { 6.5} for a
The solution set is { 6.2 } for b
2006-09-23 03:00:19 · answer #3 · answered by SAMUEL D 7 · 0⤊ 0⤋
2a + 5b = 44 eq 1
-6a +5b = -8 eq 2
--------------------------------
8a = 52
a = 52/8
a = 6 1/2
using substitution:
2(6 1/2) + 5b = 44
13 + 5b = 44
5b = 44 - 13
5b = 31
b = 31/5 or
b = 6 1/5
To check the values:
2( 6 1/2) + 5( 6 1/5 ) = 44
13 + 31 = 44
44 = 44
2006-09-23 01:22:38 · answer #4 · answered by hanna 3 · 0⤊ 0⤋
OK, let' see:
2a+ 5b = 44
-6a+5b = 8
From first equation: 2a = 44-5b
Multiplying by -3 = -6a= -132 + 15b
Subs in second equation,
-132 + 15b +5b = 8
20b = 140
b = 7
Solving for a,
2a = 44 - 5b = 44- 5(7)
2a = 9
a = 9/2
Good luck.
2006-09-23 01:06:06 · answer #5 · answered by alrivera_1 4 · 0⤊ 0⤋
2a + 5b = 44
5b - 6a = 8
Multiply bottom by -1
2a + 5b = 44
-5b + 6a = -8
8a = 36
a = (9/2)
2a + 5b = 44
2(9/2) + 5b = 44
9 + 5b = 44
5b = 35
b = 7
a = (9/2)
b = 7
2006-09-23 02:34:11 · answer #6 · answered by Sherman81 6 · 0⤊ 0⤋
something is wrong with the question
2006-09-23 03:26:31 · answer #7 · answered by Anonymous · 0⤊ 0⤋