Answer:
Step-by-step explanation:
x(x+8) = 450
x² + 8x - 450 = 0
Quadratic formula:
x = [-8±√(8²-4(1)(-450))]/[2(1)]
= [-8±2√466]/2
= -4±√466
≅ 17.59, -25.59
-25.59 is an extraneous solution, so x ≅ 17.6 inches.
The dimensions of the blackboard are 17.59 inches by 25.59 inches
