SOLUTION: I need help on these questions for math. It's on " Elimination using Multiplication " 4x - y = 9 5x + 2y = 8 And on this problem 6x -4y = -8 4x + 2y = -3

Algebra ->  Expressions-with-variables -> SOLUTION: I need help on these questions for math. It's on " Elimination using Multiplication " 4x - y = 9 5x + 2y = 8 And on this problem 6x -4y = -8 4x + 2y = -3      Log On


   



Question 1014306: I need help on these questions for math. It's on " Elimination using Multiplication "
4x - y = 9
5x + 2y = 8
And on this problem 6x -4y = -8
4x + 2y = -3

Answer by ikleyn(52803) About Me  (Show Source):
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I need help on these questions for math. It's on " Elimination using Multiplication "
4x - y = 9
5x + 2y = 8
And on this problem 6x -4y = -8
4x + 2y = -3
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1.

4x -  y = 9   (1)
5x + 2y = 8   (2)

Multiply the equation (1) by 2 (both sides and all the terms) and then add to the equation(2). You will get

8x + 5x = 2*8 + 9,   or

13x = 26.

Hence, x = 26%2F13 = 2.

Then from (1) y = 4x - 9 = 4*2 -9 = 8-9 = 1.

Solved.


2.

6x - 4y = -8    (1)
4x + 2y = -3    (2)

Multiply equation (2) by 2 and then add to the equation (1).

From this point please complete the solution yourself.