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

y² + 7y + 12 = 0
(y + 3)(y + 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y + 3) or (y + 4) must equal zero:

If (y + 3) = 0, y must equal -3
If (y + 4) = 0, y must equal -4

So the solution is that y = -3 or -4

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 2 x 1) + (2 x 1 x 4) + (2 x 2 x 4)
sa = (4) + (8) + (16)
sa = 28

A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(2 + 9)(5)
a = ½(11)(5)
a = ½(55) = \( \frac{55}{2} \)
a = 27\(\frac{1}{2}\)

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.