Solve for x. Show the equation you used and your work. Question 2 options:
1 answer:
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Answer:
Width = 18, height = 3
Or
Width = 6, height = 9
Step-by-step explanation:
Complete question
( A piece of sheet metal 24 inches wide is bent to form a gutter as shown in the picture below, if the cross sectional area is 54 square inches, find the depth of the gutter).
X = width, Y = height
X - 2y = 24........ equation i
X = 24 - 2y.......... equation ii
Area = xy
54 = xy........ equation iii
Put equation ii into equation iii
54 = (24 - 2y) * y
54 = 24y - 2y²
2y² - 24y + 54 = 0........ equation iv
Solving equation iv using quadratic methods,
Factors = (y-3), (y-9)
(Y-3)(y-9) = 0
y = 3 or y = 9
Substitute y = 3 or y = 9 into equation ii
X = 24 -2(3) = 18 or x = 24 - 2(9) = 6
If Width = 18, height = 3
Or
Width = 6, height = 9
The horizontal line has equation . The line is solid, and everything below it is shaded, which translates to the inequality
. (so not B nor D)
The dashed line must have equation . Because it's dashed, the inequality is strict. Pick any point in the shaded region, (0, 0) for instance, and compare both sides of this equation. (0, 0) means both
and
, so on the left side we have 0, and on the right we have -1. 0 > -1, so the inequality must be
.
This means the answer is A.