HELP IM BEING TIOMED

-2.1

Step-by-step explanation:

x= 4/5

you put in 4/5 where x is supposed to be so you get: -2/5 - 4/5 + (-9/10)

-2/5 - 4-5 = -6/5

-6/5= -12/10

-12/10 + -9/10= -21/10 = -2.1

c

step-by-step explanation:

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.