Đáp án:
CHÚC BẠN HỌC TỐT!!!
Giải thích các bước giải:
$c, 3+2^{x-1}=24-[4^2-(2^2-1)]$
$⇔3+2^{x-1}=24-13=11$
$⇔2^{x-1}=11-3=8$
$⇔2^{x-1}=2^3$
$⇔x-1=3$
$⇔x=4$
$d, (\dfrac{11}{12}+\dfrac{11}{12.23}+\dfrac{11}{23.34}+...+\dfrac{11}{89.100})+x=\dfrac{5}{3}$
Đặt $A=\dfrac{11}{12}+\dfrac{11}{12.23}+\dfrac{11}{23.34}+...+\dfrac{11}{89.100}$
$A=\dfrac{1}{1}-\dfrac{1}{12}+\dfrac{1}{12}-\dfrac{1}{23}+\dfrac{1}{23}-\dfrac{1}{34}+...+\dfrac{1}{89}-\dfrac{1}{100}$
$A=1-\dfrac{1}{100}=\dfrac{99}{100}$
$A+x=\dfrac{5}{3}$
$⇒\dfrac{99}{100}+x=\dfrac{5}{3}$
$⇒x=\dfrac{5}{3}-\dfrac{99}{100}=\dfrac{203}{300}$
