x-42= -15+27÷3mũ2
Rút gọn phân số: a) 6.12-6.7/60 ; b) 35.18-35/(34).7; c) 42-11.42/21.(-15); d) 2mũ5 . 3mũ2/2mũ2 .8.3mũ3 e) (-36).14 / 14.3mũ3 + 7.3mũ3
a: \(=\dfrac{6\left(12-7\right)}{60}=\dfrac{6\cdot5}{6\cdot10}=\dfrac{5}{10}=\dfrac{1}{2}\)
b: \(=\dfrac{35\cdot\left(18-1\right)}{34\cdot7}=5\cdot\dfrac{1}{2}=\dfrac{5}{2}\)
c: \(=\dfrac{42\left(1-11\right)}{21\cdot\left(-15\right)}=2\cdot\dfrac{-10}{-15}=2\cdot\dfrac{2}{3}=\dfrac{4}{3}\)
d: \(=\dfrac{2^5\cdot3^2}{2^5\cdot3^3}=\dfrac{1}{3}\)
e: \(=\dfrac{-36\cdot14}{27\left(14+7\right)}=\dfrac{-36}{27}\cdot\dfrac{14}{21}=\dfrac{-4}{3}\cdot\dfrac{2}{3}=-\dfrac{8}{9}\)
Mik vẫn chwua hiểu câu hỏi
x-15=42
x =42-15
x =27
sai rồi nha
x = 42+15
x = 57
vậy ......
Trl :
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x-42= -15+27:3^2
x-42=-15+27:9
x-42=-15+3
x-42=-12
x=-12+42
x=30
Vậy x=30
Tìm x, biết:
a) ( 35 - x ) - 25 = 40 - ( 15 - 18 )
b) x + 42 = -15 + 27 : 3 ^ 2
c) 27 - ( 5 - | x | ) = 31
a/ ( 35-x)-25=40-(15-18)
(35-x)-25=40-(-3)
(35-x)-25=43
35-x=43+25
35-x=68
x=35-68
x= -33
b/ x+42=-15+27: 3^2
x+42=-15+27 : 9
x+42=-15+3
x+42=-12
x=-12 -42
x= -54
a) (35-x)-25=40-(15-18)
(35-x)-25=43
35-x=43-25=18
x=35-18=17
b)x+42=(-15)+27:3^2
x+42=-12
x= (-12)-42
x=-54
c)27-(5-|x|)=31
5-|x|=27-31=-4
|x|=5-(-4)
|x|=9
=>x=9 hoặc -9
X-42= -15+27÷3^2
x-42= -15+27÷3^2
x-42= -15+27÷9
x-42= -15+3
x-42= -12
x= -12+42
x= 42-12
x= 30
Chúc bạn học tốt!
X - 42 = - 15 + 27 : 32
X - 42 = - 15 + 27 : 9
X - 42 = - 15 + 3
X - 42 = - 12
X = ( - 12 ) + 42
X = 30
X -42=-15+27:32
=> x -42= -15 +27 :9
=> x-42 = -15 +3
=> x-42= -12
=>x= 42+-12
=> x=30
g) (15 + 37) + (52 – 37 – 17) h) (38 – 42 +14) - (38 – 42 - 15) i) (27 + 65 ) + (346 - 27- 65) k) - (27 + 65) - (346 – 27 - 65) l) (42 – 69 + 17) - (42 + 17) m) 24. (16 - 5) – 16. (24 – 5 ) n) (-12). 47 – 12 . 52 + (-12) p) 51 . (69 - 25) – 69. (51 - 25) |
g) (15 + 37) + (52 – 37 – 17) = 15 + 37 + 52 – 37 – 17 = 15 + 52 – 17 = 50 h) (38 – 42 +14) - (38 – 42 - 15) = 38 – 42 +14 - 38 + 42 + 15 = 14 + 15 = 29 i) (27 + 65 ) + (346 - 27- 65) = 27 + 65 + 346 - 27- 65 = 346 k) - (27 + 65) - (346 – 27 - 65) = -27 - 65 - 346 + 27 + 65 = -346 l) (42 – 69 + 17) - (42 + 17) = 42 – 69 + 17 - 42 - 17 = – 69 m) 24. (16 - 5) – 16. (24 – 5 ) = 24. 16 - 24 . 5 - 16 . 24 + 16. 5 = - 24 . 5 + 16. 5 = -8 . 5 = -40 n) (-12). 47 – 12 . 52 + (-12) = -12 (47 - 52 + 1) = -12 . (-4) = 48 p) 51 . (69 - 25) – 69. (51 - 25) = 51 . 69 - 51 . 25 – 69. 51 + 69. 25 = - 51 . 25 + 69. 25 = (- 51+ 69).25 = 450 |
Bài1: Tính a) (-38).47+147.38 , b) 37.42-142.37+15 , c)46.115-14.46+(-46)
Bài 2 Tìm x: a) 27-(27-x)=45 , b) -18+42=42-2x
Bài 2 Tìm x: a) 27-(27-x)=45 ,
27+x-27=45
x=45
b) -18+42=42-2x
24=42-2x
2x=42-14
2x=28
x=14
1)
a) (-38).47+147.38
= 38.(147 - 47)
= 38 . 100 = 3800
b) 37.42-142.37+15
= 37.(42 - 142) + 15
= 37. (-100) + 15
= -3700 + 15 = -3685
c) 46.115-14.46+(-46)
= 46.(115 - 14 - 1)
= 46 . 100 = 4600
2)
a) 27-(27-x) = 45
27-x = 27 - 45
27-x = -18
x = 27 + 18
=> x = 45
Vậy x = 45
b) -18+42=42-2x
2x = 42 + 18 - 42
2x = 18
=> x = 9
Vậy x = 9
Chúc em học tốt!!!
Bài 3. Tìm x. x/36 = 3/4 ; x/7 = 56/49 ; 15/27 = 5/x ; 3/7 = 42/x