To solve this equation, isolate the variable for which you are solving (b) on one side of the equation and put everything else on the other side.

b + 9x = 4b - 4x + 3
b = 4b - 4x + 3 - 9x
b - 4b = -4x + 3 - 9x
-3b = -13x + 3
b = \( \frac{-13x + 3}{-3} \)
b = \( \frac{-13x}{-3} \) + \( \frac{3}{-3} \)
b = 4\(\frac{1}{3}\)x - 1

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.

An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite:

d° = b° + c°

To find angle c, remember that the sum of the interior angles of a triangle is 180°:

180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 46° - 58° = 76°

So, d° = 58° + 76° = 134°

A shortcut to get this answer is to remember that angles around a line add up to 180°:

a° + d° = 180°
d° = 180° - a°
d° = 180° - 46° = 134°

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).

To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce -45 as well and sum (Inside, Outside) to equal 4. For this problem, those two numbers are -5 and 9. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 4y - 45
y² + (-5 + 9)y + (-5 x 9)
(y - 5)(y + 9)