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 8 x 3) + (2 x 3 x 4) + (2 x 8 x 4)
sa = (48) + (24) + (64)
sa = 136

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

-9y + 5 = \( \frac{y}{-6} \)
-6 x (-9y + 5) = y
(-6 x -9y) + (-6 x 5) = y
54y - 30 = y
54y - 30 - y = 0
54y - y = 30
53y = 30
y = \( \frac{30}{53} \)
y = \(\frac{30}{53}\)

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(5²) + 2π(5 x 9)
sa = 2π(25) + 2π(45)
sa = (2 x 25)π + (2 x 45)π
sa = 50π + 90π
sa = 140π

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.

4a⁶ + 2a⁶ = 6a⁶

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.