Question

M 2 = 2x°, m 3 = 5x°, m 1 =

2x + 5x
5x - 2x
180 - 5x
180 - 7x

Answer 1

We know: the sum of measures of triangle angles is 180°.

Therefore we have the equation

`m\angle1+m\angle2+m\angle3=180^o\to m\angle1=180^o-m\angle2-m\angle3`

Substitute
`m\angle2=2x,\ m\angle3=5x`:

`m\angle1=180-2x-5x=180-7x`

Answer: 180 - 7x