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

5a + z = 1
z = 1 - 5a

then substitute the result (1 - 5a) into the second equation:

a + 7(1 - 5a) = 3
a + (7 x 1) + (7 x -5a) = 3
a + 7 - 35a = 3
a - 35a = 3 - 7
-34a = -4
a = \( \frac{-4}{-34} \)
a = \(\frac{2}{17}\)

The area of a parallelogram is equal to its length x width:

a = l x w
a = a x b
a = 7 x 9
a = 63

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.

4a⁶ - 5a⁶ = -1a⁶

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 c° = 18, the value of d° is 162.

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.