4 x 7 = 30 - x.

What is the value of x ?

x = 2

Step-by-step explanation:

Given

4 x 7 = 30 - x

First solve the left side . When you multiply, we have

28 = 30 - x

Combine like term. When -x crosses over equality sign , it becomes positive x , and 28 becomes -28

So ,

x = 30 - 28

x = 2

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.

can you complete your sentence? i could !