Here is a function - OCR - GCSE Maths - Question 17 - 2018 - Paper 1
Question 17
Here is a function.
Function A: Input → + 14 → x 5 → Output.
(a) The output of function A is x.
Write an algebraic expression, in terms of x, for the input of fun... show full transcript
Worked Solution & Example Answer:Here is a function - OCR - GCSE Maths - Question 17 - 2018 - Paper 1
Step 1
Write an algebraic expression, in terms of x, for the input of function A.
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Answer
To find the input of function A in terms of the output x, we can reverse the operations applied in the function. The output x is produced by first multiplying the input by 5 and then adding 14. Therefore, we can express the input as follows:
Start with the output:
x=5imesInput+14
Rearrange the equation to isolate the input:
x−14=5×InputInput=5x−14
Thus, the algebraic expression for the input of function A is: Input=5x−14
Step 2
Find the value of k.
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Answer
Given that the output is also k, we can substitute k for the output in the expression derived in part (a):
Set the original equation equal to k:
k=5×Input+14
We also know that the input is k, so:
k=5k+14
Rearranging this gives:
k−5k=14−4k=14k=−414k=−27