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).

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 37° - 44° = 99°

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.

6a - 9a = -3a

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses.

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

-c + x = 9
x = 9 + c

then substitute the result (9 - -1c) into the second equation:

9c + 7(9 + c) = 1
9c + (7 x 9) + (7 x c) = 1
9c + 63 + 7c = 1
9c + 7c = 1 - 63
16c = -62
c = \( \frac{-62}{16} \)
c = -3\(\frac{7}{8}\)