Question

How do I do this

f(x) = x - 5 (x + 4)^(1/2)

when f(x) = -5

I know I can just guess and chekc but I want to know how to do this algebraically by subsituting in -5 and trying to solve for x which I don't know how to do...

so

-5 = x - 3 (x + 4)^(1/2)
how do I solve for x??

also why does 22/7 = pi????

Answer 1

so you are looking at the equation

-5 = x - 3√(x+4)
3√(x+4) = x+5
square both sides
9(x+4) = x^2 + 10x + 25
x^2 + x - 11 = 0
solving this by the quadratic formula gave me
x = (-1 ±√45)/2 or appr. 2.854 or -3.854


BTW, 22/7 is not equal to pi, it is merely a reasonable approximation as a fraction.
pi is an irrational number, that is, it cannot be written exactly as a fraction or as a decimal.