Question

Angels ABC and DEF are supplementary angles. The measure of angle ABC, in degrees, is given by the expression 2x + 10. The measure of angle DEF, in degrees, is given by the expression 3x - 15. What is the value of x?

Answer 1

x = 31°

Explanation:

Recall ;

Supplemtary angles summ up to 180°

Given that :

ABC and DEF are Supplementary angles and hence sum up to 180°

ABC + DEF = 180°

(2x + 10) + (3x + 15) = 180

2x + 10 + 3x + 15 = 180

2x + 3x + 10 + 15 = 180°

5x + 25° = 180°

5x = 180 - 25

5x = 155

x = 155 / 5

x = 31°