Cho f(x) = (x – 4) – 3(x+1). Tìm x sao cho f(x) = 4 28/10/2021 Bởi Camila Cho f(x) = (x – 4) – 3(x+1). Tìm x sao cho f(x) = 4
$f(x)=x-4-3(x+1)=x-4-3x-3=-2x-7$ $f(x)=4\to -2x-7=4$ $\to -2x=11$ $\to x=\dfrac{-11}{2}$ Vậy $f\Big(\dfrac{-11}{2}\Big)=4$ Bình luận
f(x)=4
⇒(x-4)-3(x+1)=4
⇔x-4-3x-3=4
⇔x-3x=4+3+4
⇔-2x=11
⇔x=-11/2
vậy x =-11/2
$f(x)=x-4-3(x+1)=x-4-3x-3=-2x-7$
$f(x)=4\to -2x-7=4$
$\to -2x=11$
$\to x=\dfrac{-11}{2}$
Vậy $f\Big(\dfrac{-11}{2}\Big)=4$