1 tính = cách hợp lí
a,36.23+62.23+46
2.tìm x
a,47. x +213=3.7.3.7
b,83+519.x=66.100+22
1.tinh = cach hơp li
a.36.23+62.23+46
2.tim x
a,47.x+213=3.7.3.7
b,82+519.x=6.100+22
Câu 2:
a: =>47x+213=21x21=441
=>47x=228
hay x=228/47
b: =>519x=540
=>x=540/519=180/173
Bài 2: (1.5 điểm) Tìm x, biết: (83 + 519).x = 66.100 + 22. Kết quả:
(83 + 519).x = 66.100 + 22
602 .x = 6622
x = 6622 : 602
x = 11
\(\left(83+519\right).x=66.100+22\)
\(\Leftrightarrow602.x=6622\)
\(\Leftrightarrow x=6622\div602\)
\(\Rightarrow x=11\)
Vậy x=11
chúc bạn hok tốt.bye
1.
a,25.17.8.4.125
2.Tìm x
a.47.x+213=3.7.37
b.(83+519).x=66.100+22
x x
x
a, 25.17.8.4.125=1700000
2,Tìm x
a,47x+213=3.7.37 => 47x+213=777 => 47x=777-213=564 =>x=564/47=12
b,(83+519)x=66.100+22 =>(83+519)x = 6622
=> 602.x =6622
=>x=11
1)25.17.8.4.125=25.17.32.25.5=25.(17.32.5)=25.2720=68000
2)
a)4.x+213=3.7.37 b)(83+519).x=66.100+22
4.x+213=777 602.x=6622
4.x=777-213 x=6622:602
4.x=564 x=11
x=564:4
x=141
[83+519]x=66*100+22
(83 + 519) . x = 66 . 100 + 22
(83 + 519) . x = 6600 + 22
(83 + 519) . x = 6622
602 . x = 6622
x = 6622 : 602
x = 11
tính một cách hợp lí
a, 28 x 7,32 - 7,32 : 0,125
`28 xx 7,32 - 7,32 : 0,125`
`= 28 xx 7,32 - 7,32 xx8`
`= 7,32 xx(28-8)`
`= 7,32 xx20`
`=146,4`
Tính hợp lí
a) 762 - (325 - 138) + 125
b) -56.731 - 56.70 + 56
c)- (671 - 563) + (-462 - 129 -122)
d) -342 - (3485 + 234 + 158) - (-3485)
a: =762-325+138+125
=900-200=700
b; =-56(731+70-1)=-56*800=-44800
c: =-671+563-462-129-122
=-1384+563
-821
d: =-342-3485-234-158+3485
=-734
Tính hợp lý:
1, 1+(-4)+7+(-10)+13
2, -2+7+(-12)+17+(-22)
3, 44+45+46+47-24-25-26-27
4, (-213)+186+(-14)+217+54+(-49)
`@` `\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`
Tính hợp lí
a) 1/2 x 1 x 1/3 x 10 x 7/35 x 3/4
\(\dfrac{1}{2}\cdot1\cdot\dfrac{1}{3}\cdot10\cdot\dfrac{7}{35}\cdot\dfrac{3}{4}\)
\(=\dfrac{1}{2}\cdot10\cdot\dfrac{1}{5}\cdot1\cdot\dfrac{1}{3}\cdot\dfrac{3}{4}\)
\(=\dfrac{10}{10}\cdot\dfrac{1}{4}=\dfrac{1}{4}\)
2023 x 14 + 2023 x 83 +97
78 x 31 + 78 x 24 + 78 x 17 + 78 x 22 x 72
371 x 69 + 371 x 14 + 629 x 83
91 x 51 + 49 x 163 - 49 x 72
3 x 12 x 17 + 4 x 9 x 81 + 2 x 6 x 6
42 x 17 + 58 x 83 x 42 x 83 + 42 x 83 + 58 x 17
tính bằng cách hợp lý nhất
`@` `\text {Ans}`
`\downarrow`
`2023 \times 14 + 2023 \times 83+97`
`= 2023 \times (14+83) + 97`
`= 2023 \times 97 + 97`
`= 196231 +97`
`= 196328`
`78 \times 31+78 \times 24+78 \times 17+78 \times 22 \times 72`
`= 78 \times (31+24+17+22 \times 72)`
`= 78 \times (31+24+17+1584)`
`= 78 \times 1656`
`= 129168`
`371 \times 69+371 \times 14+629 \times 83`
`= 371 \times (69+14) + 629 \times 83`
`= 371 \times 83 + 629 \times 83`
`= 83 \times (371+629)`
`= 83 \times 1000`
`= 83000`
`91 \times 51+49 \times 163-49 \times 72`
`= 91 \times 51 + 49 \times (163-72)`
`= 91 \times 51+49 \times 91`
`= 91 \times (51+49)`
`= 91 \times 100`
`= 9100`
`3 \times 12 \times 17 + 4 \times 9 \times 81 + 2 \times 6 \times 6`
`= 9 \times 4 \times 17 + 4 \times 9 \times 81 + 4 \times 9 \times 2`
`= 9 \times 4 \times (17+81+2)`
`= 36 \times 100`
`= 3600`
`42 \times 17 + 58 \times 83 \times 42 \times 83 + 42 \times 83 + 17`
`= 17 \times (42+58) + 42 \times 83 \times (58 \times 83 +1)`
`= 17 \times 100 + 3486 \times 4815`
`= 1700 + 16785090`
`= 16786790`