To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

3a(a - y)
3(-2)(-2 - 5)
3(-2)(-7)
(-6)(-7)
42

To solve this equation, isolate the variable for which you are solving (a) on one side of the equation and put everything else on the other side.

4a - 5y = 3a + 3y + 5
4a = 3a + 3y + 5 + 5y
4a - 3a = 3y + 5 + 5y
a = 8y + 5

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

6a⁶ + 8a⁶ = 14a⁶

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 1 x 5) + (2 x 5 x 8) + (2 x 1 x 8)
sa = (10) + (80) + (16)
sa = 106

A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r²h and the surface area is 2(π r²) + 2π rh.