Biết Lim 3f( x) - 2g(x)= 4

Chọn A

Ta có \[\mathop {\lim }\limits_{x \to 2} \left[ {3f\left( x \right) - 2g\left( x \right)} \right] = 4\] và \[\mathop {\lim }\limits_{x \to 2} \left[ {f\left( x \right) + 3g\left( x \right)} \right] = 5\] ta suy ra \[\mathop {\lim }\limits_{x \to 2} f\left( x \right) = 2\] và \[\mathop {\lim }\limits_{x \to 2} g\left( x \right) = 1\].

Do vậy \[\mathop {\lim }\limits_{x \to 2} \left[ {4f\left( x \right) + 5g\left( x \right)} \right] = 4\mathop {\lim }\limits_{x \to 2} f\left( x \right) + 5\mathop {\lim }\limits_{x \to 2} g\left( x \right) = 13\].