6. Find the value of x for which ABCD must be a parallelogram.BO916x - 15CA30+ 11xD

SOLUTION
Given the question in the image, the following are the solution steps to answer the question.
STEP 1: State the appropriate side theorem that applies to the given question
Opposite sides of a parallelogram have equal lengths. This means that:
[tex]|BC|=|AD|[/tex]STEP 2: Write the measures of the two sides
[tex]\begin{gathered} |BC|=16x-15 \\ |AD|=30+11x \end{gathered}[/tex]STEP 3: Find the equation that applies
According to the statement in Step 1,
[tex]16x-15=30+11x[/tex]STEP 4: Solve for x
[tex]\begin{gathered} 16x-15=30+11x \\ 16x-11x=30+15 \\ 5x=45 \\ \frac{5x}{5}=\frac{45}{5} \\ x=9 \end{gathered}[/tex]Hence, x = 9