Question

figure lmno is a parallelogram.
what is the value of x?
8
10
13
20

Explanation:

Step1: Use parallelogram consecutive angles property

Consecutive angles in a parallelogram are supplementary, so their sum is $180^\circ$.
$$(8x - 40) + 3x = 180$$

Step2: Combine like terms

Add the $x$ terms together.
$$11x - 40 = 180$$

Step3: Isolate the $x$ term

Add 40 to both sides of the equation.
$$11x = 180 + 40$$
$$11x = 220$$

Step4: Solve for $x$

Divide both sides by 11.
$$x = \frac{220}{11}$$

Answer:

20