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

-7c + z = -6
z = -6 + 7c

then substitute the result (-6 - -7c) into the second equation:

2c - 1(-6 + 7c) = 8
2c + (-1 x -6) + (-1 x 7c) = 8
2c + 6 - 7c = 8
2c - 7c = 8 - 6
-5c = 2
c = \( \frac{2}{-5} \)
c = -\(\frac{2}{5}\)

A line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.

The sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 34° - 62° = 84°

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.

3a + 8a = 11a

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².