Difference of squares: Using quadrilaterals

The area of a rectangle is equal to $(4x+9)(4x-9)$.

Calculate x.

$\operatorname{\pm}3$

The area of the parallelogram below is 56.

BE is its height.

Calculate x.

$9$

The area of the parallelogram is equal to $(x+3)(x-3)$.

Calculate x.

$\pm6$

The area of the rectangle below is 132.

Calculate x.

$\pm7$

The area of the rectangle below is equal to: $(3x+4)(3x-4)$.

Calculate a x.

$$

$\operatorname{\pm}3$

The area of the rectangle below is equal to $(x-7)(x+7)$.

Calculate x.

$\pm12$