Đáp án:
a) \(f\left( 1 \right) = \dfrac{3}{2}\)
Giải thích các bước giải:
\(\begin{array}{l}
y = f\left( x \right) = 1,5x = \dfrac{3}{2}x\\
a)f\left( 1 \right) = \dfrac{3}{2}.1 = \dfrac{3}{2}\\
f\left( { - 1} \right) = \dfrac{3}{2}.\left( { - 1} \right) = - \dfrac{3}{2}\\
f\left( { - 2} \right) = \dfrac{3}{2}.\left( { - 2} \right) = - 3\\
f\left( 2 \right) = \dfrac{3}{2}.2 = 3\\
f\left( 0 \right) = \dfrac{3}{2}.0 = 0\\
b)Thay:y = - 1\\
\to - 1 = \dfrac{3}{2}x \to x = - \dfrac{2}{3}\\
Thay:y = 0\\
\to 0 = \dfrac{3}{2}x \to x = 0\\
Thay:y = 4,5 = \dfrac{9}{2}\\
\to \dfrac{9}{2} = \dfrac{3}{2}.x \to x = 3\\
c)y > 0 \to \dfrac{3}{2}x > 0 \to x > 0\\
y < 0 \to \dfrac{3}{2}x < 0 \to x < 0
\end{array}\)
