Question

solve for a in the parallelogram below.
6a + 45
2a + 21

Explanation:

Step1: Set equal opposite sides

In a parallelogram, opposite sides are congruent, so we set the expressions equal:
$6a + 45 = 2a + 21$

Step2: Subtract $2a$ from both sides

Isolate $a$-terms on one side:
$6a - 2a + 45 = 21$
$4a + 45 = 21$

Step3: Subtract 45 from both sides

Isolate the $a$-term:
$4a = 21 - 45$
$4a = -24$

Step4: Divide by 4 to solve for $a$

Calculate the value of $a$:
$a = \frac{-24}{4}$

Answer:

$a = -6$