Question

(1 điểm) Cho hàm số y = f(x) = 3x ^ 2 - 3 +2
a) Tính (1), f(- 2)
b) Tìm x khi f(x) = 2

Answer 1

a) \(f\left(1\right)=3.1^2-3+2=3-3+2=2\)

\(f\left(-2\right)=3.\left(-2\right)^2-3+2=12-3+2=11\)

b) \(f\left(x\right)=2\Rightarrow3x^2-3+2=2\)

\(\Rightarrow3x^2-1=2\)

\(\Rightarrow3x^2=2+1\)

\(\Rightarrow3x^2=3\)

\(\Rightarrow x^2=1\)

\(\Rightarrow x=-1;x=1\)