5. X-
15. 24×2 + 32x - 96 -
3×2 + 4x – 12-
X-
X-
16. 4.56×2 + 7.89x – 7.65 -
X-
-
-
X-
17. x2 -
x2 + 3x -6-
x-
x-
18. x / (x + 7) -
x2 + 6x – 7-
the LCD for the denominators is (x+7)(x-1)
multiply both sides by (x+7)(x-1)
x(x - 1)-
x2-x-
6. x2+11x-12-
(x+12)(x-1)-
x-
when x-
So the solution to the equation is x-
19. Jim made a 350 mile trip in his car at a certain speed. If he had gone 10 mph fa
ster, he could have
made the trip in one hour less time. Find his speed.
Let x represent his speed.
The time he made a 350 mile trip is 350/x hour.
If he had gone 10 mph faster, the speed is (x+10) mph, then the time he made a 35
0 mile trip is
350/(x+10) hour, which is 1 hour less. So we can make an equation:
350/x - 350/(x+10)-
Multiply both sides by x(x+10):
350(x + 10) - 350x-
x2 + 10x - 3500-
x-
x-
Jim’s speed is 54.37 mph
7. 20. The Monahan’s garden is 20 feet by 30 feet.
They wish to lay a uniform border of pine bark
around the garden. How large a strip should they lay if they only have enough bark
to cover 420
square feet? (…and don’t tell me to buy more pine bark…:) )
let x represent the width of the border
the overall dimensions of border and garden is: (2x+20)feet by (2x+30)feet
the area of the garden is 20 * 30 -
The total area of border & garden is (420 + 600) sq ft, which can also express
ed as: (2x+20)(2x+30).
So here is the equation:
(2x+20) * (2x+30) -
4×2 + 100x + 600-
X2 + 25x -105-
(x+26)(x-1)-
X-
So the strip should be 1 foot.
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