\(a,\Rightarrow2^{x-1}=24-\left(16-3\right)-3\\ \Rightarrow2^{x-1}=24-13-3\\ \Rightarrow2^{x-1}=8=2^3\\ \Rightarrow x-1=3\Rightarrow x=4\\ b,\Rightarrow\left(19x+50\right):14=25-16=9\\ \Rightarrow19x+50=126\\ \Rightarrow x=4\)

b1:

a,\(\frac{3}{8}:\frac{5}{4}\)=\(\frac{3}{8}.\frac{4}{5}=\frac{12}{45}=\frac{4}{15}\)

b,\(\frac{4}{7}:\frac{2}{13}=\frac{4}{7}.\frac{13}{2}=\frac{26}{7}\)

b2:

a,25:0,1=250              25x10=250            42:0,01=4200              42x100=4200           72:0,1=720           83:0,01=8300

b,13:0,25=52              13x4=52                42:0,5=84                   42x2=84                  75:0,5=150           125:0,25=500

3/8:5/4=3/10

4/7:2/13=26/7

9

a,25:0,1=250

25.10=250

42:0,01=4200

42.100=4200

72:0,1=720

83:0,01=8300

b,13:0,25=52

13.4=52

42:0.5=84

42.2=422

75/0,5=150

125:0.25=500

= 3/10

=26/7

 = 250

= 250

= 4200

=4200

=720

=8300

=52

=52

=84

=150

=500

kết quả theo thứ tự từ trên xuống nhé 

\(a.=24+42+120-24-42\)

\(=\left(24-24\right)+\left(42-42\right)+120\)

\(=0+0+120\)

\(=120\)

\(b.=13-145+49-13-49\)

\(=\left(13-13\right)+\left(49-49\right)-145\)

\(=0+0-145\)

\(=-145\)

a)(24+42)+(120-24-42)

= 24+42+120- 24-42

=(24-24)+(42-42)+120

=0+0+120

=120

b)(13-145+49)-(13+49)

= 13-145+49-13+49

= (13-13)+(49-49)+145

= 0+0+145

=145

c)25.2²+(15-28)+(12-19+10)

=25.4+15-28+12-19+10

=100+(19-15)-(28+12)+10

=100+4-40+10

=94

# Hok_tôt

bai toán kho @gmail.com

a, 13 - 18 - ( - 42 ) -1 5 = 22

c,(-8 ) ^ 3 : ( - 8 ) ^ 2 +8 = 0

câu a=22 nhé

a ) 13 - 18 - ( - 42 ) - 15    

= 13 - 18 + 42 - 15        

= -5 + 42 - 15                  

= 37 - 15                      

= 22                             

cảm ơn bạn nhiều

Đề khó nhìn quá bạn ơi!

Lời giải:

a.

$8750:35=250$

$23520:56=420$

$11780:42=280$ dư 20$

b.

$2996:28=107$

$2420:12=201$ dư $8$

$13870:45=308$ dư $10$

.

A) 8750 : 35 = 250

23520 : 56 = 420

11780 : 42 = 5890/21

B) 2996 : 28 = 107

2420 : 12 = 605/3

13870 : 45 = 2774/9