Equation is 2(3x+24)=9x+18
Answer is x=10
Bisector means it cuts it in half so ABD is the same as DBC. The whole angle is 9x+18 which is the same as doubling 3x+24 since thats half of if hence the equation 2(3x+24)=9x+18
To solve for x you have to distribute 2(3x+24) by multiplying 2 to 3x and 24
New equation is 6x+48=9x+18
Subtract 6x both sides
48=3x+18
Subtract 18 both sides
30=3x
Divide both sides by 3
10=x