Answer:
- 525 = (w+4)(w)
- 21 ft by 25 ft
Step-by-step explanation:
Let w represent the width of the floor. Then the length of the floor is (w+4) and its area is ...
A = LW
525 = (w+4)(w)
w^2 +4w -525 = 0
(w -21)(w +25) = 0 . . . . factor the above
Solutions are ...
w = 21, w = -25
We are interested in the positive solution: w = 21.
The floor is 21 feet wide and 25 feet long.
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<em>Alternate solution</em>
Sometimes, when the factors aren't obvious, it works well to write an equation for the average of the dimensions. Here, we can represent that with x, and use (x-2) for the width, and (x+2) for the length. Then we have ...
525 = (x-2)(x+2) = x^2 -4
529 = x^2
√529 = 23 = x
Then w=23 -2 = 21, and the length is w+4 = 25.
It equal to 24 because you have to multiply or divide first then you can add or subtract
Answer: 24, 33
2.5, 4.75
9.5, 11.75
<u>Step-by-step explanation:</u>
It is given that the PERIMETER is BETWEEN 24 and 33
--> 24 < P < 33
Graph: O------------------O
24 33
Perimeter = 2w + 2L
It is given that L = w + 7
Substitute P with 2w + 2L and substitute L with w + 7
24 < 2w + 2(w + 7) < 33
24 < 2w + 2w + 14 < 33
10 < 4w < 19
--> 2.5 < w < 4.75
Graph: O--------------------------O
2.5 4.75
Since L = w + 7, then w = L - 7
Substitute P with 2w + 2L and substitute w with L - 7
24 < 2(L - 7) + 2L < 33
24 < 2L + 2L - 14 < 33
38 < 4L < 47
--> 9.5 < L < 11.75
Graph: O------------------------O
9.5 11.75
<em>NOTE: Make sure you use OPEN dots on the graphs.</em>
Answer:
x=-4 y=-7
Step-by-step explanation:
-4x+y=9 get y alone
add 4x both sides
y=4x+9
insert into y=2x+1
2x+1=4x+9
subtract 1 both sides
2x=4x+8
subtract 4x both sides
-2x=8
divide by -2
x=-4
y=2x+1
y=2(-4)+1
y=-8+1
y=-7
check
-4(-4)+(-7)=9
-16+(-7)=9
9=9
x=-4
y=-7
gl