7.(x-5)-3.(4-x)
=7x-35-12+3x
=10x-47
thay x=-1 vào 10x-47 ,có:
10.(-1)-47=-57
Các câu hỏi tương tự
bai 5 : tinh
a) tim x , biet (x+1) +(x+2 ) + ...+(x+100)=5750
b) chung minh rang B = 1/2^2 + 1/3^2 + 1/4^2 + ...+1/2021^2 < 1
giup mik luon voi
2.3^x=40.3^12 + 8 : 7^4
giup mik voi mik dang can gap
a) tim gia tri nho nhat cua bieu thuc : A = | 1-x | + 8
b) tim cac so nguyen x biet 13 la boi cua x - 4
c) tim so nguyen x sao cho ( x + 5 ) chia het cho ( x + 3 )
giup minh voi! minh can gap gap gap.....
khong tinh gia tri cu the hay so sanh :
A = 1998 x 2002 voi B = 2000 x 2000
B = 35 x 53 - 18 voi D = 35 + 53 x 34
mn giup mik nhanh nhe ~~ mik can rat gap
giup mk nhanh voi minh can gap lam:tim x thuocZ biet:
10-x-|x+5|=0 va |x-7|+|x+3|=8
a) 92/9 + 13/5 - 56/9
b) 58/7 - (31/9 + 30/7)
c) 2/3 + 1/3 x 9/4 - 13/12
d) 41/8 - 7/4 : 11/5
e) 478/19 : 5/4 - 668/19 : 5/4
f) 32/21 x 49/45 : 16/22 x 15/33
g) 2020x2018+9 / 2019x2020-2011.
Giup minh voi minh dang can gap!!!
1 tim x , biet
a) x - 7va 5/8 = 1 va 1/4
b) x + 7 va 5/8 = 9 va 1/4
c) ( x - 7 va 5/8 ) : 1/2 = 3
d) x / 1x3 + x/3x5+.....+x/97x99=99
giup mik nhanh nha . mik can gap lam
mik dag can gap
tim x
a,2.3^x=162
2.2^2x+4^3.4^x=1506
x^20=x
giup mik voi
47/53. ( 17/3 - 53/47) + 17/3 .( 6/17 - 47/53)
5/7 . ( 1/2 -1/3 +4/7 ) + ( 1/3 - 1/2 -4/7 ) :7/5
tim x
3 (x-1/2 ) - 5 ( x- 2/3) = 3/2x
help me mik dang can gap . cam on