Answer:
add 21 to both sides to get everything on one side
x^2 - 10x + 21 = 0
do factorization, guess and check
(x - 7) (x -3) = 0
x =7, and x =3
Answer:
Length of the rectangle = 16 inches
Width of the rectangle = 12 inches
Step-by-step explanation:
Let the length of the rectangle be represented by x.
Then width can be expressed as ![\[\frac{x}{2}+4\] ](https://tex.z-dn.net/?f=%5C%5B%5Cfrac%7Bx%7D%7B2%7D%2B4%5C%5D%0A)
Perimeter of a rectangle is the sum of four sides of the rectangle.
This can be expressed as 2*(length + breadth)
= ![\[2* (x + \frac{x}{2}+4)\]](https://tex.z-dn.net/?f=%5C%5B2%2A%20%28x%20%2B%20%5Cfrac%7Bx%7D%7B2%7D%2B4%29%5C%5D)
= ![\[2* (\frac{3x}{2}+4)\]](https://tex.z-dn.net/?f=%5C%5B2%2A%20%28%5Cfrac%7B3x%7D%7B2%7D%2B4%29%5C%5D)
= ![\[3x + 8\]](https://tex.z-dn.net/?f=%5C%5B3x%20%2B%208%5C%5D)
But perimeter is given as 56.
So, ![\[3x + 8 = 56\] ](https://tex.z-dn.net/?f=%5C%5B3x%20%2B%208%20%3D%2056%5C%5D%0A)
=> ![\[3x = 48\]](https://tex.z-dn.net/?f=%5C%5B3x%20%3D%2048%5C%5D)
=> ![\[x = 16\]](https://tex.z-dn.net/?f=%5C%5Bx%20%3D%2016%5C%5D)
Hence length of the rectangle = 16 inches
Width of the rectangle = ![\[\frac{16}{2}+4\]](https://tex.z-dn.net/?f=%5C%5B%5Cfrac%7B16%7D%7B2%7D%2B4%5C%5D)
= 12 inches
Answer:
x=11/5, or x=2.2.
Step-by-step explanation:
9-3(x+4)=2(x-3)-8
9-3x-12=2x-6-8
9-12-3x=2x-14
-3-3x=2x-14
-3-3x-2x=-14
-3-5x=-14
5x=-3-(-14)
5x=-3+14
5x=11
x=11/5
x=2.2
Answer:$0.25 per apple
$0.30 per orange
Step-by-step explanation:
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Answer:
The even numbers between 0 and X represents an arithmetic sequence with a common difference of 2
The rule of arithmetic sequence = a + d(n - 1)
Where a is the first term and n is the number of terms
So, for the even numbers between 0 and X
The first term = a = 0
d = 2
So, we need to find n at the last term which is X
∴ X = 0 + 2 ( n -1 )
∴ n - 1 = X/2
∴ n = X/2 + 1
The sum of the arithmetic sequence = (n/2) × (2a + (n−1)d)
Substitute with a and d and X
So, the sum = (n/2) * (2*0 + (n−1)*2)
= (n/2) * ((n−1)*2)
= n(n-1)
= (X/2 + 1) * (X/2)
= X/2 by (X/2 + 1)
So, The quick way to add all even numbers between 0 and X always works.
