Linear Equations
Solve for x.
7(x+5)+4(x+5)=6x-6
A. x=5
B. x=-61/17
C. x=-61/5
D. x=21/5

C. x = -61/5

Step-by-step explanation:

7(x+5)+4(x+5) = 6x-6

7x+35 + 4x+20 = 6x-6

11x + 55 = 6x - 6

5x + 55 = -6

5x = -61

x = -61/5

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.