SOLUTION: The width of a rectangle is 3 ft, its length is (6x + 2) ft, and its area is 80 ft². Find x.

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Question 459524: The width of a rectangle is 3 ft, its length is (6x + 2) ft, and its area is 80 ft². Find x.

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

The width of a rectangle is W=3+ft,
the length is L=%286x+%2B+2%29+ft, and
the area is A=80+ft%5E2
Find x:
A=80+ft%5E2
L%2AW=80+ft%5E2
%286x+%2B+2%29+ft%2A3+ft=80+ft%5E2
3%286x+%2B+2%29+ft%5E2=80+ft%5E2
3%286x+%2B+2%29+cross%28ft%5E2%29=80cross%28+ft%5E2%29
3%286x+%2B+2%29+=80
18x+%2B+6+=80
18x+=80-6
18x+=74
x+=74%2F18
x+=4.11
so,
L=%286x+%2B+2%29+ft=%286%2A4.11%2B2%29ft=%2824.66%2B2%29ft=26.66ft

check:
L%2AW=80+ft%5E2
26.66ft%2A3ft=80+ft%5E2
79.98ft%5E2=80+ft%5E2...round up
80ft%5E2=80+ft%5E2