Find the measure of the exterior angle.

u = 143º

Step-by-step explanation:

Sum of angles in a triangle is 180

The unknown angle IN the triangle

x + 90 + 53 = 180

x + 143 = 180

x = 37º

x and u are supplementary angle which total 180

u + 37 = 180

u = 143º

option 3 . (5x + 1) - (-10x + 6)

step-by-step explanation:

option 1 :

(4x + 3) + (-9x + 4)

or 4x+3 -9x + 4

or -5x + 7

option 2

(x - 2) - (6x - 9)

or x-2-6x + 9

or -5x + 7

option 3

(5x+ + 6)

or 5x + 1 + 10x -6

or 15x -5

option 4

-4x+2x+7-3x

-7x + 2x + 7

-5x + 7

hence only option 3 did   not satisfy the given simplify expression.