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.

-9a + 3y = -2a + y - 4
-9a = -2a + y - 4 - 3y
-9a + 2a = y - 4 - 3y
-7a = -2y - 4
a = \( \frac{-2y - 4}{-7} \)
a = \( \frac{-2y}{-7} \) + \( \frac{-4}{-7} \)
a = \(\frac{2}{7}\)y + \(\frac{4}{7}\)

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

sa = 2πr² + 2πrh
sa = 2π(9²) + 2π(9 x 3)
sa = 2π(81) + 2π(27)
sa = (2 x 81)π + (2 x 27)π
sa = 162π + 54π
sa = 216π

According to the Pythagorean theorem, the hypotenuse squared is equal to the sum of the two perpendicular sides squared:

c² = a² + b²
c² = 5² + 3²
c² = 25 + 9
c² = 34
c = \( \sqrt{34} \)

Parallel lines are lines that share the same slope (steepness) and therefore never intersect. A transversal occurs when a set of parallel lines are crossed by another line. All of the angles formed by a transversal are called interior angles and angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°) and are called corresponding angles. Alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°) and all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other. Same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°).

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.