Answer:
19 1/3°
Step-by-step explanation:
Given the expressions ABF=(7x+20)° m angle FBC=[2x-5)° and m angle ABC=159°
The addition properties is there fore true for the three angles;
<ABC = <ABF+<FBC
159 = 7x+20+2x-5
159 = 9x-15
Add 15 to both sides
159+15 = 9x-15+15
174 = 9x
9x = 174
Divide both sides by 9
9x/9 = 174/9
x = 19 1/3°
The value of x is 19 1/3°
