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
