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`@` `\text {Ans}`
`\downarrow`
`e)`
`1+(-4)+7+(-10)+13`
`= (-4 - 10) + (1 + 13) + 7`
`= -14+14 + 7`
`= 7`
`f)`
`-2+7+(-12)+17+(-22)`
`= (7 + 17) + (-12 - 22) - 2`
`= 24 - 34 - 2`
`= -10 - 2`
`= -12`
`g)`
`44+45+46+47-24-25-26-27`
`= (44 - 24) + (45 - 25) + (46 - 26) + (47 - 27)`
`= 20 + 20 + 20 + 20`
`= 20*4 = 80`
a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)
\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)
\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)
b) \(\dfrac{39}{7}:x=13\)
\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)
c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)
\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)
\(\dfrac{14}{5}x=34+50=84\)
\(x=\dfrac{84}{\dfrac{14}{5}}=30\)
d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)
e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)
\(\dfrac{1}{6}x=\dfrac{5}{12}\)
\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)
g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)
\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)
\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)
\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)
\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)
h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)
\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)
\(x=1\)
Mỏi tay woa bn làm nốt nha!!
Bài 2:
a) 1 + (-4) + 7 + (-10) + 13 + (-35)
= [1 + (-4) + (-10)] + [7 + (-35)] + 13
= -13 + (-28) + 13
= [-13+13] + (-28)
=0 + (-28)
= -28
b) -2 + 7 . (-12) + 17 . (-22) + 27
= -2 + (- 84) + (-374) + 27
= -86 + (-374) + 27
= -460 + 27
= -433
Bài 3 với Bài 4 mình ko có TG để ghi từng dòng nên mình chỉ ghi đáp án thôi nhé
Bài 3:
a)56 + (-29)+ (-7) + 28 +13 + (-16)
=45
b)1316 + 317 + (-14) + 217 + 54 (-49)
=810
Bài 4:
a)435 + (-43) + (-483) + 383 + (-415)
=-123
b)1316 + 317 + (-1216) + (-315) +(-85)
=17
#Học tốt
&YOUTUBER&
1+2+3+4+5+6+7+8+9+10=55
11+12+13+14+15+16+17+18+19+20=155
1+2+3+4+5+6+7+8+9+10+11+12+13+14 +15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30-50-53=362
\(1+2+3+4+5+6+7+8+9+10=55\)
\(11+12+13+14+15+16+17+18+19+20=155\)
`@` `\text {Ans}`
`\downarrow`
`1,`
\(1+(-4)+7+(-10)+13\)
`= 1+(7+13)+(-4-10)`
`= 1+10-14`
`= 11-14`
`= -3`
`2, `
\(-2+7+(-12)+17+(-22)\)
`= -2+(7+17)+(-12-22)`
`= -2 + 24 - 24`
`= -2`
`3,`
\(44+45+46+47-24-25-26-27\)
`= (44 - 24)+(45 - 25) + (46 - 26)+(47 - 27)`
`= 20 + 20 + 20 + 20`
`= 40`
`4,`
\((-213)+186+(-14)+217+54+(-49)\)
`= (186 + 54)+(-213-14-49) + 217`
`= 240 - 276 + 217`
`= -36 + 217 = 181`