I kinda get the regular problems, but the word problems just completely stump me. If anyone could help, that'd be great :)
1) The difference of the squares of two consecutive odd integers is 24. Find the integers.
2) The length of a garden is 20 yards greater than its width. The area is 300 square yards. What are the dimensions?
1) The difference of the squares of two consecutive odd integers is 24. Find the integers.
2) The length of a garden is 20 yards greater than its width. The area is 300 square yards. What are the dimensions?
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1) let x be first odd number
x+2 be the second
so (x+2)^2-x^2 = 24
x^2+4x+4-x^2 = 24
4x +4 = 24
4x = 20
x = 5
first odd number = 5
second = 7
to check: 7^2-5^2 =49-25+24 :))
2) let x be the width
x+20 be the length
area =300
area = length x width
300 = (x+20)(x)
300 = x^2+20x
x^2+20x-300=0 ...use quadratic or factor out like this:
(x +30) (x-10) =0
then x+30 = 0 x - 10=0
x = -30 x =10
and it's obviously both positive cause it's area. so dimensions are 30 and 10 yards
x+2 be the second
so (x+2)^2-x^2 = 24
x^2+4x+4-x^2 = 24
4x +4 = 24
4x = 20
x = 5
first odd number = 5
second = 7
to check: 7^2-5^2 =49-25+24 :))
2) let x be the width
x+20 be the length
area =300
area = length x width
300 = (x+20)(x)
300 = x^2+20x
x^2+20x-300=0 ...use quadratic or factor out like this:
(x +30) (x-10) =0
then x+30 = 0 x - 10=0
x = -30 x =10
and it's obviously both positive cause it's area. so dimensions are 30 and 10 yards
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1. let x be the largest odd integer
let x-2 be the smallest odd integer.
the difference of the two odd integer is 24 so
(x)^2 - (x-2)^2=24
x^2-x^2+4x-4 = 24 cancel x^2
4x-4=24 transpose -4 to the right side
4x=24+4
4x=28 divide both sides by 4
x=7
substitute 7 to x-2
it gives 5
the integers are 5 and 7.
2. let L be the length
let W be the width
L = 20+W
W = W
formula for the rectangle is
A = L * W
(20+W)*(W) = 300 sq.yards
20W + W^2 = 300 sq. yards transpose 300 to the left side.
W^2 + 20W -300=0 by quadratic factoring.
it gives
(W+30)(W-10)=0
W = -30 , 10 but negative is not valid the width is 10
the dimension is 30yards X 10 yards
let x-2 be the smallest odd integer.
the difference of the two odd integer is 24 so
(x)^2 - (x-2)^2=24
x^2-x^2+4x-4 = 24 cancel x^2
4x-4=24 transpose -4 to the right side
4x=24+4
4x=28 divide both sides by 4
x=7
substitute 7 to x-2
it gives 5
the integers are 5 and 7.
2. let L be the length
let W be the width
L = 20+W
W = W
formula for the rectangle is
A = L * W
(20+W)*(W) = 300 sq.yards
20W + W^2 = 300 sq. yards transpose 300 to the left side.
W^2 + 20W -300=0 by quadratic factoring.
it gives
(W+30)(W-10)=0
W = -30 , 10 but negative is not valid the width is 10
the dimension is 30yards X 10 yards
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(2n+1)^2 - (2n-1)^2 = 24
8n = 24
n = 3
Numbers 7 and 5
49-25 = 24
x(x+20) = 300
x^2 + 20 x + 100 = 400
(x+10)^2 = 20^2
x+10 = 20 ( only + 10)
x = 10
8n = 24
n = 3
Numbers 7 and 5
49-25 = 24
x(x+20) = 300
x^2 + 20 x + 100 = 400
(x+10)^2 = 20^2
x+10 = 20 ( only + 10)
x = 10
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1) (x+2)^2 -x^2 =24
x^2 +4x +4 -x^2 = 24
4x =20
x= 5
x+2= 7
2)Area = l x w = 300yds^2
l and l-20
l x(1+20)
l^2 +20 l =300
l^2 +20l -300 =0
(l +30)(l-10)
l =30
w= 10
x^2 +4x +4 -x^2 = 24
4x =20
x= 5
x+2= 7
2)Area = l x w = 300yds^2
l and l-20
l x(1+20)
l^2 +20 l =300
l^2 +20l -300 =0
(l +30)(l-10)
l =30
w= 10