Alexis wrote 28 - 8 = 20. Then she wrote 28 -8 + 9 = 20 – 9. Are her
equations balanced? Explain.

no this is because 28-8+9=29 and 20-9=11

Step-by-step explanation:

Her equation is not balanced.

Because 28 - 8 + 9 = 20 - 9

                 29 = 11 ( its not balanced)

She put the  same symbol or sign on both side.Here she put different sign on both side .so this equation is not balanced.

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.