Suppose f(x)=Ax+B for real constants A and B. If f(60)=70 and f(72)=79, find k such that f(k)=k.
PLEASE HELP :]
Ok we have f(x)=Ax+B which is a line.
We also know
(1) f(60)=70 which means A*60+B=70
(2) f(72)=79 " " A*72+B=79
Which means A*12=9 if we subtract (1) from (2). Thus A=3/4 and B=25
Now we want (3/4)k+25=k or (1/4)k=25
You can finish and verify it.
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