a . - 18 -x = - 8 + ( 13)
b . x - 43= ( 57 - x ) - 50
c . - 4 ( 2x + 9) - ( - 8x +3 ) - ( x + 13) = 0
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a) \(\left(42\times43+43\times57+43\right)-360:4\)
\(=43\times\left(42+57+1\right)-90\)
\(=43\times100-90\)
\(=4300-90\)
\(=4210\)
b) \(\left(372-19\times4\right)+\left(981:9-13\right)\)
\(=\left(4\times93-19\times4\right)+\left(109-13\right)\)
\(=4\times\left(93-19\right)+109-13\)
\(=4\times74+109-13\)
\(=296+109-13\)
\(=392\)
c) \(456:2\times18+456:3-102\)
\(=456\times\frac{1}{2}\times18+456\times\frac{1}{3}-102\)
\(=456\times\left(\frac{1}{2}\times18+\frac{1}{3}\right)-102\)
\(=456\times\left(9+\frac{1}{3}\right)-102\)
\(=456\times\frac{28}{3}-102\)
\(=4256-102\)
\(=4154\)
ko bk tính nhanh!
a)( 42 x 43 + 57+43 ) - 360 :4 b) (372 - 19 x 4 ) + ( 981 : 9 - 13 )
= 43 x (42 + 57 +1 ) - 90 = (372 - 76 ) + ( 109 - 13)
= 43 x 100 - 90 = 296 + 96
= 4300 - 90 = 392
= 4210
a) \(x+5=20-\left(12-7\right)\)
\(\Rightarrow x+5=20-5\)
\(\Rightarrow x+5=15\)
\(\Rightarrow x=15-5\)
\(\Rightarrow x=10\)
b) \(15-\left(3+2x\right)=2^2\)
\(\Rightarrow3+2x=15-4\)
\(\Rightarrow3+2x=11\)
\(\Rightarrow2x=11-3\)
\(\Rightarrow2x=8\)
\(\Rightarrow x=\dfrac{8}{2}\)
\(\Rightarrow x=4\)
c) \(-11-\left(19-x\right)=50\)
\(\Rightarrow19-x=-11-50\)
\(\Rightarrow19-x=-61\)
\(\Rightarrow x=61+19\)
\(\Rightarrow x=80\)
d) \(159-\left(25-x\right)=43\)
\(\Rightarrow25-x=159-43\)
\(\Rightarrow25-x=116\)
\(\Rightarrow x=25-116\)
\(\Rightarrow x=-91\)
e) \(\left(79-x\right)-43=-\left(17-52\right)\)
\(\Rightarrow\left(79-x\right)-43=52-17\)
\(\Rightarrow79-x-43=35\)
\(\Rightarrow36-x=35\)
\(\Rightarrow x=1\)
f) \(\left(7+x\right)-\left(21-13\right)=32\)
\(\Rightarrow7+x-8=32\)
\(\Rightarrow x-1=32\)
\(\Rightarrow x=32+1\)
\(\Rightarrow x=33\)
g) \(-x+20=-15+8+13\)
\(\Rightarrow-x+20=6\)
\(\Rightarrow x=20-6\)
\(\Rightarrow x=14\)
h) \(-\left(-x+13-142\right)+18=55\)
\(\Rightarrow x-13+142+18=55\)
\(\Rightarrow x+147=55\)
\(\Rightarrow x=55-147\)
\(\Rightarrow x=-92\)
a) (x – 45).27 = 0 ó x – 45 = 0 ó x = 45
b) 41.(2x – 8).13 = 0 ó 2x – 8 = 0 ó x = 4
c) (x – 36):18 = 12 ó x – 36 = 12.18 ó x = 216 + 36 ó x = 252
d) 43.(x – 18) = 86 ó x – 18 = 86:43 ó x = 2+18 ó x = 20
e) 96 : (121 – x) = 4 ó 121 – x = 96 : 4 ó 121 – x = 24 ó x = 121 – 24 ó x = 97
f) 340 : (15x+5) = 17 ó 15x + 15 = 340 :17 ó 15x + 5 = 20 ó 15x = 20 – 5 ó 15x = 15 ó x = 1
= [43 x ( 42 + 57 + 1)] - 90
= (43 x 100) -90
= 4300 - 90
= 4210
a,( 42 x 43 + 43 x 57 + 43 ) - 360 : 4
= [ 43 x ( 42 + 57 + 1 ) ] - 90
= [ 43 x 100 ] - 90
= 4300 - 90
= 4210
b, 372 - 19 x 4 - 981 : 9 - 13
= 372 - 76 - 109 - 13
= 174
c, 452 : 2 x 18 - 456 : 3 - 102
= 226 x 18 - 152 - 102
= 4068 - 152 - 102
= 3814
phép tính này có quy tắc :
nhân chia trước, cộng trừ sau.
trong ngoặc trc ngoài ngoặc sau
tíc mình nha
(42 x 43 + 43 x 57 + 43) - 360 : 4
= 4426549 - 360 : 4
= 4426549 - 90
= 4426459
(372 - 19 x 4 + (981 : 9 - 13)
= 296 + 96
= 392
456 : 2 x 18 + 456 : 3 - 102
= 4104 + 50
= 4154
>_< học tốt
\(a.\)
\(-18-x=-8+\left(13\right)\)
\(\Rightarrow-18-x=5\)
\(\Rightarrow x=-18-5=-23\)
\(b.\)
\(x-43=\left(57-x\right)-50\)
\(\Rightarrow x-43=57-x-50\)
\(\Rightarrow x+x=43+57-50\)
\(\Rightarrow2x=50\)
\(\Rightarrow x=25\)
\(c.\)
\(-4\left(2x+9\right)-\left(-8x+3\right)-\left(x+13\right)=0\)
\(\Rightarrow-8x-36+8x-3-x-13=0\)
\(\Rightarrow-x-52=0\)
\(\Rightarrow-x=52\)
\(\Rightarrow x=-52\)