Question

f (x) = 5x^2-4.
a) f (2); f (-3); f (0).
б) Найти аргумент, если
f (x) = -4; f (x) = 1.

Answer 1

a) f(2)=5*2^2-4 f(2)=16;  f(-3)=5*(-3)^2-4=41;  f(0)=5*0-4=-4

б) f(x)=-4
-4=5x^2-4
5x^2=0
x^2=0
x=0

f(x)=1
1=5x^2-4
5x^2=5
x^2=1
x=1; x=-1