You have to multiply by the complex conjugate so that you can clear the radical from the denominator.
Once you do the multiplication simplify the radical. There's still a common factor in -54, -18, & 75 so divide all those by 3.
The answer is 5. Measure r and t are congruent. Measure r is 20 so measure t is also 20. So by dividing 20 by 4 you get 5.
Answer:
3x+18
Step-by-step explanation:
3 (x+6)
Distribute
3x+3*6
3x+18