1) Let's sketch that
The area of the parallelogram is base x height so we can write:
x(x+6) =48
x²+6x = 48 Completing the square
x² +6x +9 = 48 +9
(x+3)²= 57
√(x+3)² =√57
x+3 = √57
x_1=√57-3,
x_2=-√57-3
Since there can't be negative numbers for geometric measures
x=√57-3 ⇒ 7.55 -3 x =4.55 (approximately)