Giúp em bài 2 , 4
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
Anh trả lời giúp em có thể cho anh 1 lượt vote ko?
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 3:
a. $[25+(-15)]+(-25)=25-15-25=(25-25)-15=0-15=-15$
b. $512-(-88)-400-112$
$=512+88-400-112$
$=(512-112-400)+88=(400-400)+88=88$
c.
$-(310)+(-290)-907+107=-310-290-907+107$
$=-(310+290)-(907-107)=-600-600=-1200$
d.
$-2004-1975+2000-2025$
$=-(2004-2000)-(1975+2025)=-4-4000=-(4+4000)=-4004$
Bài 1:
a. $ax+ay+bx+by=(ax+ay)+(bx+by)=a(x+y)+b(x+y)$
$=(x+y)(a+b)=17(-2)=-34$
b. $ax-ay+bx-by = (ax-ay)+(bx-by)$
$=a(x-y)+b(x-y)=(x-y)(a+b)=(-1)(-7)=7$
![](https://rs.olm.vn/images/avt/0.png?1311)
Cách 1:
\(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\times\dfrac{4}{9}\)
\(=\dfrac{5}{9}\times\dfrac{4}{9}\)
\(=\dfrac{20}{81}\)
Cách 2:
\(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\times\dfrac{4}{9}\)
\(=\dfrac{1}{3}\times\dfrac{4}{9}+\dfrac{2}{9}\times\dfrac{4}{9}\)
\(=\dfrac{4}{27}+\dfrac{8}{81}\)
\(=\dfrac{20}{81}\)
C1: \(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\)x\(\dfrac{4}{9}\)=\(\left(\dfrac{3}{9}+\dfrac{2}{9}\right)\text{x}\dfrac{4}{9}\)=\(\dfrac{5}{9}\text{x}\dfrac{4}{9}=\dfrac{20}{81}\)
C2: \(\left(\dfrac{1}{3}+\dfrac{2}{9}\right)\)x\(\dfrac{4}{9}\)=\(\dfrac{1}{3}\text{ x}\dfrac{4}{9}+\dfrac{2}{9}\text{ x}\dfrac{4}{9}\)=\(\dfrac{4}{27}+\dfrac{8}{81}=\dfrac{12}{81}+\dfrac{8}{81}=\dfrac{20}{81}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 4:
\(a,\Rightarrow5⋮x\Rightarrow x\inƯ\left(5\right)=\left\{1;5\right\}\\ b,\Rightarrow x-2+7⋮x-2\\ \Rightarrow x-2\inƯ\left(7\right)=\left\{1;7\right\}\\ \Rightarrow x\in\left\{3;9\right\}\\ c,\Rightarrow3\left(x+1\right)+4⋮x+1\\ \Rightarrow x+1\inƯ\left(4\right)=\left\{1;2;4\right\}\\ \Rightarrow x\in\left\{0;1;3\right\}\\ d,\Rightarrow10x+6⋮2x-1\\ \Rightarrow5\left(2x-1\right)+11⋮2x-1\\ \Rightarrow2x-1\inƯ\left(11\right)=\left\{1;11\right\}\\ \Rightarrow x\in\left\{1;6\right\}\\ e,\Rightarrow x\left(x+3\right)+11⋮x+3\\ \Rightarrow x+3\inƯ\left(11\right)=\left\{1;11\right\}\\ \Rightarrow x=8\left(x\in N\right)\\ f,\Rightarrow x\left(x+3\right)+2\left(x+3\right)+5⋮x+3\\ \Rightarrow x+3\inƯ\left(5\right)=\left\{1;5\right\}\\ \Rightarrow x=2\left(x\in N\right)\)
Bạn cần ghi đề bài ra nhé!