Question

Find the value of x.

Answer 1

x = 15.

Explanation:

By the External angle of a triangle theorem:-

The external angle = the sum of the 2 opposite internal angles.

So:

10x - 23 = 7x - 26 + 5x - 27

10x - 7x - 5x = -27 - 26 + 23

-2x = -30

x = 15.

Answer 2

x=15

Explanation:

`\angle A+\angle B+\angle C=180^\circ\\(5x-27)^\circ+(7x-26)^\circ+[180^\circ-(10x-23)^\circ]=180^\circ\\12x-53+180-10x+23=180\\2x-30+180=180\\2x-30=0\\2x=30\\x=15`