B1 :36:3 ²+2.4 ²
2021-2020:[420 -2 ².(4.3 ²+8 ²)]
125.34+125.16 -50.25
-546+[(-274)+546+374]
B2 : 50-2x=4^4 :4 ²
(3x-2) ³ = 64
lx-1l=4-(-2)
B1 :36:3 ²+2.4 ²
2021-2020:[420 -2 ².(4.3 ²+8 ²)]
125.34+125.16 -50.25
-546+[(-274)+546+374]
B2 : 50-2x=4^4 :4 ²
(3x-2) ³ = 64
lx-1l=4-(-2)
Bài 1:
a) 36:3^2+2.4^2
= 36:9+2.16
= 4+32
= 36
b) = 2021-2020:[420-4.(4.9+64)]
= 2021-2020:[420-4.(36+64)]
= 2021-2020:[420-4.100]
= 2021-2020:[420-400]
= 2021-2020:20
= 2021-101
= 1920
c) 125.34+125.16 -50.25
= 125.(34+16)-50.25
= 125.50-50.25
= 50.(125-25)
= 50.100
= 5000
d) -546+[(-274)+546+374]
= -546+564+[(-274)+374]
= 0+ [+(374-274)]
=0+100
=100
B2
a) 500-2x=4^4 :4 ²
500-2x= 256:16
500-2x= 16
2x= 500-16
2x= 484
x=484:2
x= 242
b) (3x-2) ³ = 64
(3x-2)^3= 4^3
=> 3x-2= 4
3x= 4+2
3x= 6
x= 6:3
x= 2
Đáp án:
Giải thích các bước giải:
Bài 1
36:3 ²+2.4 ²=36:9+2.16=4+32=36
2021-2020:[420 -2 ².(4.3 ²+8 ²)]=2021-2020:[420-4(4.9+64)
=2021-2020:[420-4(36+64)
=2021-2020:(420-4.100)
=2021-2020:(420-400)
=2021-2020:20
=2021- 101
=1920
125.34+125.16 -50.25=125(34+16)-50.25
=125.100-50.25
=12500-1250
=11250
-546+[(-274)+546+374]=-546-274+546+374
=(-546-546)+(-274+374)
=0+100
=100
Bài 2
50-2x=4^4 :4 ²
50-2x=16
-2x=16-50
-2x=-34
x=-34:-2
x=17 Vậy x = 17
(3x-2) ³ = 64
(3x-3)³=4³
3x-3=4
3x=4+3
3x=7
x=7/3 Vậy x=7/3
lx-1l=4-(-2)
|x-1|=6
TH1:x-1=6 TH2:x-1=-6
x=6+1 x=-6+1
x=7 x=-5
Vậy x∈{7;-5}