The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

A monomial contains one term, a binomial contains two terms, and a polynomial contains more than two terms.

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

y² + 6y - 16 = -y + 2
y² + 6y - 16 - 2 = -y
y² + 6y + y - 18 = 0
y² + 7y - 18 = 0

Next, factor the quadratic equation:

y² + 7y - 18 = 0
(y - 2)(y + 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y - 2) or (y + 9) must equal zero:

If (y - 2) = 0, y must equal 2
If (y + 9) = 0, y must equal -9

So the solution is that y = 2 or -9

The volume of a cube is height x length x width:

v = h x l x w
v = 6 x 2 x 7
v = 84

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.

3a - 9a = -6a