Answer:
x = 20
Explanation:
(see attached for reference)
From the diagram, we can see that angle A and angle C are base angles of an isoceles triangle. Hence they are equal. i.e
m∠A = m∠C
(3x+10) = (2x+30)
3x+10 = 2x+30 (subtract 2x from both sides)
3x + 10 - 2x = 30
x + 10 = 30 (subtract 10 from both sides)
x = 30 - 10
x = 20