An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

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

4a + y = -5
y = -5 - 4a

then substitute the result (-5 - 4a) into the second equation:

-8a + 8(-5 - 4a) = 3
-8a + (8 x -5) + (8 x -4a) = 3
-8a - 40 - 32a = 3
-8a - 32a = 3 + 40
-40a = 43
a = \( \frac{43}{-40} \)
a = -1\(\frac{3}{40}\)

The formula for circumference is circle diameter x π. Circle diameter is 2 x radius:

c = πd
c = π(2 * r)
c = π(2 * 12)
c = 24π

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

The volume of a cylinder is πr²h:

v = πr²h
v = π(5² x 6)
v = 150π