Kevin plans to put concrete on a rectangular portion of his driveway. The portion is 10 feet long and 3 inches high. The price o
2 answers:
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Answer:
6 units
Step-by-step explanation:
Remember the formula for the area of a rectangle: A = lw
What we know:
A=48
w = l-2
Substitute A for 48 and w for l-2 into the equation
A = lw
48 = l(l-2) Use the distributive property. Multiply over the brackets.
48 = l² - 2l
Rearrange the equation to standard form (0 = ax² + bx + c) to use quadratic formula.
0 = l² - 2l - 48
a = 1 ; b = -2 ; c = -48 State the variables for the quadratic formula
Substitute a, b and c to find the length:
Simplify
Split the equation at the ± for adding and subtracting. Then decide which answer is correct, or if both of them are possible answers.
This is "inadmissable", or impossible because the length can't be a negative value.
Length of the rectangle
Use the formula for the area of a rectangle
Substitute the length and area, then isolate "w" for the width
A = lw
48 = (8)w
48/8 = w
w = 6
Therefore the length of the rectangle is 6 units.