Answer:
13) [tex]x=-3,y=4[/tex]
14) [tex]x=7, y=12[/tex]
15) [tex]x=-1,y=3[/tex]
16)[tex]x=-3,y=4[/tex]
Step-by-step explanation:
13)
[tex]y=9x+31\\6x+4y=-2[/tex]
Sub in equation 1 into equation 2.
[tex]6x+4(9x+31)=-2[/tex]
Expand the bracket.
[tex]6x+36x+124=-2[/tex]
Rearrange.
[tex]42x=-126\\x=-3[/tex]
Solve for y.
[tex]y=9(-3)+31\\y=-27+31\\y=4[/tex]
14) (Following exactly the same steps)
[tex]y=-2x+26\\-5x+2y=-11[/tex]
[tex]-5x+2(-2x+26)=-11\\-5x-4x+52=-11\\-9x=-63\\x=7[/tex]
[tex]-5(7)+2y=-11\\2y=24\\y=12[/tex]
15) (Following exactly the same steps again.)
[tex]y=2x+5\\8x+3y=1[/tex]
[tex]8x+3(2x+5)=1\\8x+6x+15=1\\14x=-14\\x=-1\\[/tex]
[tex]8(-1)+3y=1\\-8+3y=1\\3y=9\\y=3[/tex]
16) (Still no variation on how the questions are asked, exact same method)
[tex]3x+2y=-2\\y=9x+31[/tex]
[tex]3x+2(9x+31)=-1\\3x+18x+62=-1\\21x=-63\\x=-3[/tex]
[tex]y=9(-3)+31\\y=-27+31\\y=4[/tex]
