17(-84)+17(-16) , 15(58)- 15 (48) , -37(86)+3776
tính hợp lý
1, 17 (-84) + 17 (-16)
2, 15 (58) -15 (48)
3, -37 (86) + 37.76
4, 1975 (-115) + 1975.75
5, 79.89 -79 (-11)
1, 17.(-84) + 17.(-16)
= - 17.84 - 17.16
= -17.(84 + 16)
= -17.100
= -1700
2; 15.(58) - 15.(48)
= 15.(58 - 48)
= 15. 10
= 150
3, -37.86 + 37.76
= -37.(86 - 76)
= -37.10
= - 370
4, 1975.(-115) + 1975.75
= 1975. (-115 + 75)
= 1975 .(-40)
= - 79000
5, 79.89 - 79.(-11)
= 79.(89 + 11)
= 79.100
= 7900
1, 17.(-84) + 17.(-16)
= - 17.84 - 17.16
= -17.(84 + 16)
= -17.100
= -1700
2; 15.(58) - 15.(48)
= 15.(58 - 48)
= 15. 10
= 150
3, -37.86 + 37.76
= -37.(86 - 76)
= -37.10
= - 370
4, 1975.(-115) + 1975.75
= 1975. (-115 + 75)
= 1975 .(-40)
= - 79000
5, 79.89 - 79.(-11)
= 79.(89 + 11)
= 79.100
= 7900
Tính hợp lí :
17.(-84)+17.(-16)
15.(58)-15.(48)
-37.(86)+37.76
1975.(-115)+1975.15
Hãy làm đúng yêu cầu đề bài nhé !
Bạn làm được là bạn giỏi hơn tôi .
17.(-84)=17.(-16) 15.58-15.48
=17.[(-84)+(-16)] =15.(58-48)
=17.[-(84+16) =15.10
=17.(-100) =150
=-1700
-37.86+37.76 1975.(-115)+1975.15
=[-37+37].86+76 =1975.[(-115)+15]
=0.86+76 =1975.100
=0+76 =197500
=76
17.(-84)+17.(-16)
=17.\(\left[\left(-84\right)+\left(-16\right)\right]\)
=17.(-100)
=-1700
b.15.(58)-15.(48)
=15.(58-48)
=15.10=150
c.-37.(86)+37.76
=-37+37.(86+76)
=-1.162
=-162
d.1975.(-115)+1975.15
=1975.(-115+15)
=19750
x+14/86+x+15/85+x+16/84+x+17/83=-4
\(\Leftrightarrow\dfrac{x+100}{86}+\dfrac{x+100}{85}+\dfrac{x+100}{84}+\dfrac{x+100}{83}=0\)
=>x+100=0
hay x=-100
Đề bài : Dùng tính chất phân phối của phép nhân vs phép cộng để tính :
5( -3 + 2 ) - 7 * ( 5 - 4 )
3 * ( - 5 + 6 ) - 4 * ( 3 - 2 )
17 * ( - 84 ) + 17 * ( - 16 )
1975 * ( - 115 ) + 1975 * 15
- 145 * ( 13 - 57 ) + 57 * ( 10 - 145 )
157 * 17 - 157 * 7
199 * ( 15 - 17 ) - 199 * ( -17 + 5 )
- 39 * ( 5 - 99 ) + 99 * ( 10 - 39 )
- 38 * ( 25 - 4 ) + 25 * ( - 4 + 38 )
( - 37 ) * 86 + 37 * 76
Lưu ý : dấu * là nhân nha
157*(17-7)=......
(-37)*86 - (-37)*76=(-37)*(86-76)=.......
1975*(-115+15)=....
199*[(15-17)-(-17+5)]=........
17*[-84+(-16)]=.......
mn giúp mình nha
(-16)+24+16-34
25+37-48-25-37
2575+37-2576-29
34+35+36+37-14-15-16-17
\(-16+24+16-34=\left(24-34\right)+\left(16-16\right)=-10\\ 25+37-48-25-37=\left(25-25\right)+\left(37-37\right)-48=-48\\ 2575+37-2576-29=\left(2575-2576\right)+\left(37-29\right)=-1+6=5\\ 34+35+36+37-14-15-16-17=\left(34-14\right)+\left(35-15\right)+\left(36-16\right)+\left(37-17\right)=0\)
(-16)+24+16-34=24-34=-10
25+37-48-25-37=(25-25)+(37-37)-48=-48
2575+37-2576-29=8-1=7
34+35+36+37-14-15-16-17
=(34-14)+(35-15)+(36-16)+(37-17)
=20+20+20+20=20.4=80
Tinh nhanh:11+12+13+14+15+16+17+18+19+89+88+87+86+85+84+83+83+82
11+12+13+14+15+16+17+18+19+...+89+88+87+86+85+84+83+82
=( 11 + 89 )+(12+88)+(13+87)+(14+86)+(15+85)+(16+84)+(17+83)+(18+82)+19
=100+100+100+100+100+100+100+100+19
=800+19
=819
a) 415+[58+(-415) + (-38)]
b)34+35+36+37-14-15-16-17
\(a.=415+58-415-38\)
\(=\left(415-415\right)+\left(58-38\right)\)
\(=0+30\)
\(=30\)
\(b.=\left(34-14\right)+\left(35-15\right)+\left(36-16\right)+\left(37-17\right)\)
\(=20+20+20+20\)
\(=80\)
25+37-48-25-37
2575+37-2576-29
34+35+36+37-14-15-16-17
25 + 37 - 48 - 25 - 37
= (25 - 25) + (37 - 37) - 48
= 0 + 0 - 48
= -48
2575 + 37 - 2576 - 29
= (2575 - 2576) + (37 - 29)
= -1 + 8 = 7
34 + 35 + 36 + 37 - 14 - 15 - 16 - 17
= (34 - 14) + (35 - 15) + (36 - 16) + (37 - 17)
= 20 + 20 + 20 + 20
= 20 x 4
= 80
25+37-48-25-37=-48
2575+37-2576-29=7
34+35+36+37-14-15-16-17=80
k mk nhé
Giải phương trình sau
x +14/86 + x+15/85 + x+16/84 + x+17/83 + x +116/4=0
\(\dfrac{x+14}{86}+\dfrac{x+15}{85}+\dfrac{x+16}{84}+\dfrac{x+17}{83}+\dfrac{x+116}{4}=0\)
\(\Leftrightarrow\left(\dfrac{x+14}{86}+1\right)+\left(\dfrac{x+15}{85}+1\right)+\left(\dfrac{x+16}{84}+1\right)+\left(\dfrac{x+17}{83}+1\right)+\left(\dfrac{x+116}{4}-1\right)=0\)
=>x+100=0
hay x=-100