Multiply the first equation by 2 and add the new equation to the second equation.

-11x + 7y = 20

Step-by-step explanation:

See image. Multiply

2(-2x + 2y = 16)

You get -4x + 4y = 32

Then line that guy up underneath the

-15x + 3y = -12. You're adding vertically from the top down, x's with x's and y's with y's and plain numbers with plain numbers. See image

entering that problem on the tube might get you an answer

< xcy ≅ < xby

step-by-step explanation:

in δcax and δbax,

so, δcax ≅ δbax (side-angle-side or sas)

since δcax ≅ δbax, we can conclude < acx ≅ < abx

in δacy and δaby,

so, δacy ≅ δaby (side-angle-side or sas)

since δacy ≅ δaby, we can conclude < acy ≅ < aby

now,

< acy ≅ < aby

=> < acx + < xcy ≅ < abx + < xby

=> < acx + < xcy ≅ < acx + < xby   (since < acx ≅ < abx already proved above)

subtracting < acx from both sides, we get

< acx + < xcy -< acx ≅ < acx + < xby -< acx

cancelling out < acx and -< acx from both sides, we get

< xcy ≅ < xby (proved)