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.

4a⁹ - 7a⁹ = -3a⁹

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 d° = 169, the value of x° is 169.

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

8a + x = -2
x = -2 - 8a

then substitute the result (-2 - 8a) into the second equation:

7a - 3(-2 - 8a) = 6
7a + (-3 x -2) + (-3 x -8a) = 6
7a + 6 + 24a = 6
7a + 24a = 6 - 6
31a = 0
a = \( \frac{0}{31} \)
a =

The entire length of this line is represented by AD which is AB + BD:

AD = AB + BD

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.