Find the value of the expression
m + m + 9
for m = 4, n = 3, and r= 1.

111 thirty dollars is to be divided among three girls and two boys so that each of the girls receives twice as much as each of the boys. how much does each receive?

Which of the following is true for the relation f(x)=2x^2+1

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?