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

8c + x = -8
x = -8 - 8c

then substitute the result (-8 - 8c) into the second equation:

-4c - 9(-8 - 8c) = 7
-4c + (-9 x -8) + (-9 x -8c) = 7
-4c + 72 + 72c = 7
-4c + 72c = 7 - 72
68c = -65
c = \( \frac{-65}{68} \)
c = -\(\frac{65}{68}\)

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.

4a - 5a = -1a

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 15cm + 13cm + 10cm = 38cm

For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• 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°)

Applying these relationships starting with a° = 36, the value of b° is 144.

A monomial contains one term, a binomial contains two terms, and a polynomial contains more than two terms.