a. 1 và 2/9 x -5/ 11 – ( 2/3 ) mũ 2
b. 15/7 x 11 / 13 + 11 / 17 x -2/3 – 1 và 1/7
tìm x, bt
a.x/3 = 2/3 + -1/7
b. x = 3/4 + 1/ -12
c. ( 1/2 + 2x ) x 2/3 = 5/6
a. 1 và 2/9 x -5/ 11 – ( 2/3 ) mũ 2
b. 15/7 x 11 / 13 + 11 / 17 x -2/3 – 1 và 1/7
tìm x, bt
a.x/3 = 2/3 + -1/7
b. x = 3/4 + 1/ -12
c. ( 1/2 + 2x ) x 2/3 = 5/6
Đáp án:
`text{Bài 1 :}`
$a/$ `1 2/9 . (-5)/11 – (2/3)^2`
`= 11/9 . (-5)/11 – 4/9`
`= (-5)/9 – 4/9`
`= -1`
$b/$ `15/7 . 11/13 + 11/17 . (-2)/3 – 1 1/7`
`= 165/91 + (-22)/51 – 8/7`
`= ∝` `->` `text{Bạn xem lại đề bài nhé}`
`text{Bài 2 :}`
$a/$ `x/3 = 2/3 + (-1)/7`
`-> x/3 = 11/21`
`-> x = 3 . 11/21`
`-> x = 11/7`
$b/$ `x = 3/4 + 1/(-12)`
`-> x = 9/12 + (-1)/12`
`-> x = 8/12`
$c/$ `(1/2 + 2x) . 2/3 = 5/6`
`-> 1/2 + 2x = 5/4`
`-> 2x = 3/4`
`-> x = 3/8`
Bài 1 :
$a)$$1$$\frac{2}{9}$.$\frac{-5}{11}$ -($\frac{2}{3}$)²
=$\frac{11}{9}$.$\frac{-5}{11}$ -$\frac{4}{9}$
=$\frac{-5}{9}$ -$\frac{4}{9}$
=$\frac{-9}{9}$=$-1$
$b)$$\frac{15}{7}$ . $\frac{11}{13}$ +$\frac{11}{17}$ . $\frac{-2}{3}$-$1$$\frac{1}{7}$
=$\frac{165}{91}$+$\frac{-22}{51}$ -$\frac{8}{7}$
= Số lớn lắm !
Bài 2 :
a) $\frac{x}{3}$ =$\frac{2}{3}$ +$\frac{-1}{7}$
$\frac{x}{3}$ =$\frac{14}{21}$ +$\frac{-3}{21}$
$\frac{x}{3}$ =$\frac{11}{21}$
⇒$21x$=11.3
⇒ $x$=$\frac{11}{7}$
b) $x$=$\frac{3}{4}$ +$\frac{1}{-12}$
$x$=$\frac{3}{4}$ +$\frac{-1}{12}$
$x$=$\frac{9}{12}$ +$\frac{-1}{12}$
$x$=$\frac{2}{3}$
c)($\frac{1}{2}$+$2x$) . $\frac{2}{3}$ = $\frac{5}{6}$
$\frac{1}{2}$+$2x$ = $\frac{5}{6}$ : $\frac{2}{3}$
$\frac{1}{2}$+$2x$ = $\frac{5}{6}$ . $\frac{3}{2}$
$\frac{1}{2}$+$2x$ = $\frac{5}{4}$
$2x$ = $\frac{5}{4}$ – $\frac{1}{2}$
$2x$ = $\frac{5}{4}$ – $\frac{2}{4}$
$2x$ =$\frac{3}{4}$
$x$ = $\frac{3}{4}$ : 2
$x$ =$\frac{3}{4}$.$\frac{1}{2}$
$x$=$\frac{3}{8}$