Answer:
Explanation:
This is an isosceles triangle so the two down angles are equal
(5x+12) + (3x+8) = 180° (angle on a straight line is equal 180°)
Open brackets
5x+12 + 3x+8 = 180
8x + 20 = 180
Collecting like terms
8x = 180 - 20
8x = 160
Dividing by 8
x = 160/8
x = 20°