SOLUTION: Hi. My problem is: Solve the linear system by using elimination So 7x - 4y = -30 3x + 4y = 10 I tried 7x

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Question 654294: Hi. My problem is: Solve the linear system by using elimination
So
7x - 4y = -30
3x + 4y = 10
I tried

7x - 3�-2
3x. -6 + 4y = 10
10x = -20 = (-2, ). +6. +6
4y = 16 / 4 = 4 ??? Am I performing this correct? Please help. Final answer is (-2,4)
Found 2 solutions by MathTherapy, lenny460:
Answer by MathTherapy(10552) (Show Source):
You can put this solution on YOUR website!

Hi. My problem is: Solve the linear system by using elimination
So
7x - 4y = -30
3x + 4y = 10
I tried

7x - 3�-2
3x. -6 + 4y = 10
10x = -20 = (-2, ). +6. +6
4y = 16 / 4 = 4 ??? Am I performing this correct? Please help. Final answer is (-2,4)

No, you're not!!

7x - 4y = - 30 ---- eq (i)
3x + 4y = 10 ------ eq (ii)
10x = - 20 ----- Adding eqs (ii) & (i) to eliminate y and determine value of x

x = , or

7(- 2) - 4y = - 30 ----- Substituting - 2 for x in eq (i)
- 14 - 4y = - 30
- 4y = - 30 + 14
- 4y = - 16
y = , or

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Answer by lenny460(1073) (Show Source):
You can put this solution on YOUR website!
Hi. My problem is: Solve the linear system by using elimination
So
7x - 4y = -30
3x + 4y = 10
I tried

7x - 3�-2
3x. -6 + 4y = 10
10x = -20 = (-2, ). +6. +6
4y = 16 / 4 = 4 ??? Am I performing this correct? Please help. Final answer is (-2,4)

7x - 4y = -30 (eq1)
3x + 4y = 10 (eq2)

7x - 4y + 3x + 4y = -30 + 10
Combine like terms:
7x + 3x = 10x
-4y + 4y = 0
-30 + 10 = -20
Therefore:
10x = -20
Divide each side by 10
10x/10 = -20/10
x = -2

3x + 4y = 10 (eq2)
3(-2) + 4y = 10
-6 + 4y = 10
Add 6 to each side of the equation.
-6 + 4y + 6 = 10 + 6
Combine like terms:
-6 + 6 = 0
10 + 6 = 16
4y = 16
Divide each side by 4
4y/4 = 16/4
y = 4

Check:
7x - 4y = -30
7(-2) - 4(4) = -30
-14 - 16 = -30

Therefore:
The Answer:
x = -2 and y = 4

Lennox Obuong
Algebra Student
Email: obuong3@aol.com

SOLUTION: Hi. My problem is: Solve the linear system by using elimination So 7x - 4y = -30 3x + 4y = 10 I tried 7x - 3�-2 3x.