The volume of a cylinder is πr²h:

v = πr²h
v = π(4² x 9)
v = 144π

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°).

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.

5a - 8a = -3a

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

You need to find the value of a so solve the first equation in terms of x:

4a + x = -3
x = -3 - 4a

then substitute the result (-3 - 4a) into the second equation:

-8a - 6(-3 - 4a) = -3
-8a + (-6 x -3) + (-6 x -4a) = -3
-8a + 18 + 24a = -3
-8a + 24a = -3 - 18
16a = -21
a = \( \frac{-21}{16} \)
a = -1\(\frac{5}{16}\)