39*(+72)-172*38
tính cách hợp lý nhất :
a) ( - 38 ) . 63 + ( - 37 ) . 38
b) 12. 53 + 53 . 172 - 53 . 84
c) 35 . 34 + ( - 35 ) . ( - 38 ) + 65 . ( -75 ) + ( - 65 ) . 45
d ) 39 . 8 + 60 . 2 + 21.8
e) 942 - 2567 + 2563 - 1942
f) 117 . ( 217 - 116 ) + 217 . ( 116 - 117 )
mình đang cần rất gấp
504 : ( 16 - 3 . x ) = 72
( 22 . x - 52 ) . 38 = 39
\(\Rightarrow16-3x=504:72=7\\ \Rightarrow3x=16-7=9\Rightarrow x=3\\ \left(2^2\cdot x-5^2\right)\cdot3^8=3^9\\ \Rightarrow4x-25=3^9:3^8=3\\ \Rightarrow4x=28\Rightarrow x=7\)
504 : (16 - 3x) = 72 (ĐK: \(x\ne\dfrac{16}{3}\))
<=> 16 - 3x = 504 : 72
<=> 16 - 3x = 7
<=> 16 - 7 = 3x
<=> 3x = 9
<=> x = 3 (tM)
(22x - 52) . 38 = 39
<=> (4x - 25) . 6561 = 19683
<=> 4x - 25 = 19683 : 6561
<=> 4x - 25 = 3
<=> 4x = 3 + 25
<=> 4x = 28
<=> x = 7
tìm x
91-[ 27+x] = 38
39+[x-17] = 72
Ta có : 91-(27+x)=38
<=>91-27-x=38
<=>91-27-38=x
<=>x=26
39+(x-17)=72
<=>39+x-17=72
<=>x=72+17-39
<=>x=50
Tk mình nha!
\(91-\left(27+x\right)=28\)
\(27+x=91-28\)
\(27+x=63\)
\(x=63-27\)
\(x=36\)
\(39+\left(x-17\right)=72\)
\(x-17=72-39\)
\(x-17=33\)
\(x=33+17\)
\(x=50\)
hok tốt
91 - (27 + x) = 38
91 - 27 + x = 38
91 + x = 38 + 27
91 + x = 65
x = 91 - 65
x = 26
39 + (x - 17) = 72
39 + x - 17 = 72
x - 17 = 72 - 39
x - 17 = 33
x = 33 + 17
x = 40
tính nhanh
-[-171+(171+23)]-[172-(38+172)]-49
- [ - 171 + ( 171 + 23 )] - [ 172 -( 38 + 172) ] - 49
= - [ - 171 + 171 + 23] - [ 172 -38 - 172] - 49
= -23 - ( -38) - 49
= -23 +38 -49
= 15 - 49
= - 34
49 786 + 38 697
72 513 - 39 786
2 143 x 107
13 578 : 236
49 786 + 38 679 = 88465
72 513 - 39 786 = 32727
2 143 x 107 = 229301
13 578 : 236 = \(\frac{6789}{118}\)
49786 + 38697 = 88483
72513 -39785 = 32727
2143 * 107 = 229301
13578 : 236 = 57 dư
= 88 438
=32 727
=229 301
= ko chia đươc
a) 2*244+3*3*355*6+18
b)46*34+57*62+46*66+57*38
c) 172*54+172*45+172
Baì 2:Thực hiện phép tính
A)-12.(7-72)-25.(55-43)
B)(39-19):(-2)+(34-22).5
C)38.(27-44)-27(38-44)
D)237.800+(-100).(-237)
ai giúp mình bài này với
g) 101 + (–60) + 29 + (–40)
h) 167 + (–252) + 52 + (–67) i) 38 – 138 + 250 – 350
k) 118 + 107 – (118 – 93) – 50 m) 40 + (139 – 172 + 99) – (139 + 199 – 172)
\(g,101+\left(-60\right)+29+\left(-40\right)=41+29+\left(-40\right)=70+\left(-40\right)=30\)
\(h,167+\left(-252\right)+52+\left(-67\right)=\left(-85\right)+52+\left(-67\right)=\left(-33\right)+\left(-67\right)=-100\)
\(i,38-138+250-350=\left(-100\right)+250-350=150-350=-200\)
\(k,118+107-\left(118-93\right)-50=225-25-50=100-50=50\)
\(m,40+\left(139-172+99\right)-\left(139+199-172\right)=40+\left[\left(-33\right)+99\right]-\left(338-172\right)\)
\(=40+66-166=106-166=-60\)
(-172)+56+(-26)+72
Tính hợp lý
(-172)+56+(-26)+72
= [(-172)+72] + [56+(-26)]
=-100+30
=-(100-30)
=-70
Chúc bn hk tốt!
(-172) + 56 + (-26) + 72
= [(-172) + 72] + [56+(-26)]
= -100 + 30
= -70