1.Tính nhanh:a) 35.23+35.41+64.65b)29.87-29.23+64.71c)48.19+48.115+134.52d)27.121-87.27+73.34e)125.98-125.46-52.25f)136.23+136.17-40.36g)17.93+116.83+17.23h)19.27+47.81+19.20i)87.23+13.93+70.872.Tìm X:a.[(6.x-39):7].4=12b.(x:3-4).5=15c.128-3.(x+4)=23d.\(\left(3.x-3^4\right).7^3=2.7^4\)x-[42+(-28)]=-8g) x-7=-5h) 15-5.(x+4)=-12-3i) (7-x)-(25+7)=-25k)...
Đọc tiếp
1.Tính nhanh:
a) 35.23+35.41+64.65
b)29.87-29.23+64.71
c)48.19+48.115+134.52
d)27.121-87.27+73.34
e)125.98-125.46-52.25
f)136.23+136.17-40.36
g)17.93+116.83+17.23
h)19.27+47.81+19.20
i)87.23+13.93+70.87
2.Tìm X:
a.[(6.x-39):7].4=12
b.(x:3-4).5=15
c.128-3.(x+4)=23
d.\(\left(3.x-3^4\right).7^3=2.7^4\)
x-[42+(-28)]=-8
g) x-7=-5
h) 15-5.(x+4)=-12-3
i) (7-x)-(25+7)=-25
k) 0:x=0
l) \(4^x=64\)
m) \(9^{x-1}=9\)
n) \(2^x:2^5=1\)
1)
a) 35.23 + 35.41 + 64.65 = 35(23+41) + 64.65 = 35 . 65 + 64.65 =65. 99 = 65(100 - 1 ) = 6500 - 65 = 6435
b) 29.87 - 29.23 + 64.71 = 29(87-23) + 64.71 = 29.64 + 64.71 = 64(71+29) = 64.100= 6400
c) 48.19 + 48.115 + 134.52 = 48(19+115) + 134.52 = 48 . 134+134.52=134(52+48)=134.100=13400
d) 27.121 - 87.27 + 73.34 = 27(121-87) +73 .34 = 27 .34 + 73.34 = 34(73+27)=34.100=3400
e) 125.98-125.46-52.25 = 125(98-46) -52.25 = 125 . 52 - 52.25 =52(125-25) =52.100=5200
f)136.23 + 136.17 - 40.36 = 136(23+17) - 40.36 = 136.40 -40.36 = (136-36)40 = 100.40=4000
g) 17.93 + 116.83 + 17.23 = 17(93+23) + 116.83 = 17.116 + 116.83 =116(83+17) = 116.100=11600
h)19.27 +47.81 + 19.20 = 19(27+20) + 47.81 = 19. 47 + 47.81 = 47(81+19)=47.100 = 4700
i) 87.23 + 13.93 + 70.87 = 87(23+70) + 13.93 = 87 .93 + 13.93 = 93(87+13)=93.100=9300
2)Tìm x
a) [(6x-39):37].4 = 12
(6x - 39) : 37 = 12 : 4 = 3
x =(3.37 + 39): 6 = 25
b) ( x : 3 - 4 ) .5=15
x : 3 -4 = 3
x = (3+4).3 = 21
c) 128 - 3(x+4) =23
3x + 12 = 128 -23 = 105
x = (105-12):3 = 31
d) (3x - 34).73=2.74
3x - 81 = 2.74:73=2.7=14
x =(81 + 14 ) : 3= \(31\frac{2}{3}\)
e) x - [42 + (-28) ] = -8
x - 14 = -8
x- 14 + 14 = -8 + 14
x = 6
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