Given the function f(x) = 3 x - 21 + 6, for what values of x is f(x) = 18?
2 answers:
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These array of numbers shown above are called matrices. These are rectangular arrays of number that are arranged in columns and rows. It is mostly useful in solving a system of linear equations. For example, you have these equations
x+3y=5
2x+y=1
x+y=10
In matrix form that would be
![\left[\begin{array}{ccc}1&3&5\\2&1&1\\1&1&10\end{array}\right]](https://tex.z-dn.net/?f=%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%263%265%5C%5C2%261%261%5C%5C1%261%2610%5Cend%7Barray%7D%5Cright%5D%20)
where the first column are the coefficients of x, the second column the coefficients of y and the third column is the constants, When you multiple matrices, just multiply the same number on the same column number and the same row number. For this problem, the solution is
![\left[\begin{array}{ccc}3*2&0*8\\2*0.6&-1*3\end{array}\right] = \left[\begin{array}{ccc}6&0\\1.2&-3\end{array}\right]](https://tex.z-dn.net/?f=%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%2A2%260%2A8%5C%5C2%2A0.6%26-1%2A3%5Cend%7Barray%7D%5Cright%5D%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D6%260%5C%5C1.2%26-3%5Cend%7Barray%7D%5Cright%5D%20)
x+3y=5
2x+y=1
x+y=10
In matrix form that would be
where the first column are the coefficients of x, the second column the coefficients of y and the third column is the constants, When you multiple matrices, just multiply the same number on the same column number and the same row number. For this problem, the solution is
Answer:
Length: 6 m
Width: 4 m
Step-by-step explanation:
Area: 24
Width: 2L - 8 m
Length: ?
Formula: A = W * L
Replace the variables:
24 = (2L - 8) * L
24 = 2 - 8L
0 = 2 - 8L - 24
or
2 - 8L - 24 = 0
Solve; if you don't know how to solve it using this method, let me know. It's the expression
1.
2.
3.
4.
5. (L-6) (2L+4)
6. L-6 = 0 AND 2L+4 = 0
L - 6 =0
L = 6
---------------------------------
2L = -4
L =
L = -2
Since the length cannot be negative, the only real value is 6.
Area: 24
Width: 2L - 8 m
Length: 6 m
Calculate width:
W = 2L - 8
W = 2(6) - 8
W = 12 - 8
W = 4 m