Answer:
x = 13
Step-by-step explanation:
Sum or interior angles of a triangle is 180,
6x + 19 + 5x - 15 + 3x - 6 = 180
6x + 5x + 3x + 19 - 15 - 6 = 180
14x + 19 - 21 = 180
14x - 2 = 180
14x = 180 + 2
14x = 182
x = 182 / 14
690,000
c)
(10x+5)-(-23-2x)=
10x+5+23+2x
=12x+28
2x+5x^2-(3x+7x^2)=
2x+5x^2-3x-7x^2
= -2x^2-1
I uploaded a picture hope it helps
