Question

asked Jan 20, 2021 160k views

1 Answer

Wallace Campos · Answer 1 · 2021-01-24T03:30:14+0000

Answer:

13)
x=-3,y=4

14)
x=7, y=12

15)
x=-1,y=3

16)
x=-3,y=4

Explanation:

13)

$y=9x+31\\6x+4y=-2$

Sub in equation 1 into equation 2.

6x+4(9x+31)=-2

Expand the bracket.

6x+36x+124=-2

Rearrange.

$42x=-126\\x=-3$

Solve for y.

$y=9(-3)+31\\y=-27+31\\y=4$

14) (Following exactly the same steps)

$y=-2x+26\\-5x+2y=-11$

$-5x+2(-2x+26)=-11\\-5x-4x+52=-11\\-9x=-63\\x=7$

$-5(7)+2y=-11\\2y=24\\y=12$

15) (Following exactly the same steps again.)

$y=2x+5\\8x+3y=1$

$8x+3(2x+5)=1\\8x+6x+15=1\\14x=-14\\x=-1\\$

$8(-1)+3y=1\\-8+3y=1\\3y=9\\y=3$

16) (Still no variation on how the questions are asked, exact same method)

$3x+2y=-2\\y=9x+31$

$3x+2(9x+31)=-1\\3x+18x+62=-1\\21x=-63\\x=-3$

$y=9(-3)+31\\y=-27+31\\y=4$

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