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.

6a⁷ + 5a⁷ = 11a⁷

A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

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

-6a - 4 < \( \frac{a}{-1} \)
-1 x (-6a - 4) < a
(-1 x -6a) + (-1 x -4) < a
6a + 4 < a
6a + 4 - a < 0
6a - a < -4
5a < -4
a < \( \frac{-4}{5} \)
a < -\(\frac{4}{5}\)

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

z² + 7z - 8 = 0
(z - 1)(z + 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z - 1) or (z + 8) must equal zero:

If (z - 1) = 0, z must equal 1
If (z + 8) = 0, z must equal -8

So the solution is that z = 1 or -8