Kayla sold 12 blue tshirts and 36 white tshirts
Answer:
The length of side x is 
Step-by-step explanation:
Pythagorean Theorem:
In a right triangle, with sides a and b, and hypothenuse h, we have that:

In this question:
The vertical line on the sides means that both are equal, that is, measuring x, so
.
Hypothenuse is the square root of 12. So 





The length of side x is 
F(x) = 2x^2 + 5x
f(3b) = 2(3b)^2 + 5(3b) = 2(9b^2) + 15b = 18b^2 + 15b
The answer to this is 10 39/88.