Answer:
- dimensions: 12 ft by 5 ft
- area: 60 ft²
Step-by-step explanation:
Let x represent the shorter dimension in feet. Then the longer one is x+7 and the Pythagorean theorem tells us the relation of these to the diagonal is ...
x² + (x+7)² = 13²
2x² +14x + 49 = 169 . . . . eliminate parentheses
x² +7x -60 = 0 . . . . . subtract 169 and divide by 2
(x +12)(x -5) = 0 . . . . factor the equation
x = -12 or +5 . . . . . . . only the positive value of x is useful here.
The short dimension is 5 ft, so the long dimension is 12 ft. The area is their product, 60 ft².
_____
<em>Comment on finding the area</em>
The quadratic equation above can be rearranged and factored as ...
x(x +7) = 60
Since the dimensions of the garden are x and (x+7), this product is the garden's area. This equation tells us the area is 60. We don't actually have to find the dimensions.
We know that he weeds gardens for 15 hours, and mows lawns for x hours.
If he wants to earn $252 per month, we can express the following

Now, we solve for x

<h2>Hence, he has to mow lawns for 13 hours to earn at least $252.</h2>
Answer:
x+9
Step-by-step explanation:
4x³+12x²-72x
=4x(x²+3x-18)
=4x[x²+6x-3x-18]
=4x[x(x+6)-3(x+6)]
=4x(x+6)(x-3)