Question

. a) Cho hàm số y = f(x) = 2x² + 5x – 3. Tính f(1); f(0); f(1,5).

            b) Cho hàm số: y = f(x) = ax - 3

Tìm a biết f(3) = 9; f(5) = 11;  f(-1) = 6.

Answer 1

a)\(f\left(1\right)=2.1^2+5.1-3=2+5-3=4\)

\(f\left(0\right)=0+0-3=-3\)

\(f\left(1,5\right)=2.\left(1,5\right)^2-5.1,5-3=4,5-7,5-3=-6\)

 

Answer 2

b)\(f\left(3\right)=3a-3=9=>>3a=12=>a=4\)

\(f\left(5\right)=5a-3=11=>5a=14=>a=\dfrac{14}{5}\)

\(f\left(-1\right)=-a-3=6=>-a=9=>a=-9\)