Figure ABCD is a rectangle. In rectangles, <u>opposite sides are equal</u>. In the figure, BC and AD are opposite of each other, therefore their side lengths are equal. The side lengths are given: BC=9x-6, and AD=3x+12. Write this as an equation:
9x-6=3x+12
9x-3x-6=3x-3x+12 (Subtract 3x from each side of the equation)
6x-6=12
6x-6+6=12+6 (Add 6 to each side of the equation)
6x=18
x=3 (Divide each side by 6)
please let me know if this is wrong, hope it helps :)
