20) Answer is: x=76
21) Answer is x=15
Step-by-step explanation:

Square both sides of the equation.



Multiply 50 by 0.90 because you take a discount of 10% off. 1.00 = 100% 0.10 = 10% 0.01 = 1% if you multiply 50 by 0.10 instead you get the amount that is discounted instead of the new selling price.
I also think its 4 but im not sure
Answer:
0.375%
Step-by-step explanation:
i=P*R*T
$360=$8000*R/100*18/12
$360=$960R
$360/$960=$960/960
0.375%=R