use elimination by substitution..3x+y=-4,5x-4y=33

Question

I am working on elimination by substitution  the question is 3x+y=-4, 5x-4y=33 can u help me ?

Answer 1

Elimination method

Given first equation 3x+y = -4

Multiple to each side by 4.

12x+4y = -16 ---> (1)

Given second equation 5x-4y = 33 ---> (2)

To eliminate the y value add the equations (1) and (2).

12x+4y = -16

5x-4y = 33

___________

17x = 17

Divide to each side by 17.

17x/17 = 17/17

x = 1

Substitute the x value in (2).

5-4y = 33

Subtract 5 from each side.

-4y = 28

Divide to each side  by negitive 4.

-4y/-4 = 28/-4

y = -7

Solution x = 1, y = -7.