2 times the cube root of 8x+9=5
divide both sides by 2
cube root of 8x+9=2.5
cube everybody (put to 3rd power)
8x+9=2.5^3
8x+9=15.625
minus 9 both sides
8x=6.625
divie both sides by 8
x=0.828125
Area = width * height
since the window is 20 inches higher than the width:
width +20 = height
640 = width * width+20
640 = width^2 +20*width
width^2 +20*width - 640 = 0
width = 17.203
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Double Check
if width = 17.203 then height = 37.203
area = 17.203 * 37.203 = 640 square inches Correct!!
So I divided. 120 by 15 and got 8. I then multiplied it by 20 and got 160 bouquets
The answer is 40°
i will tell you how,
Total angle sum of any triangle is 180°
∠A + ∠B + ∠E = 180°
70° + 80° + ∠E = 180°
solve for ∠E
∠E = 30°
Now solve use ∠BDE,
∠B + ∠D + ∠E = 180°
20° + 90° + 30° + x = 180° (in triangle DEB, ∠E = 30 + x ) (∠D is 90°)
solve for x
there fore, x = 40°