a) 15-(x-7)=-21
x-7=15+21=36
x=36+7=43
vậy x=43
b) -12(x-5)+7(3-x)=5
-12x+60+21-7x=5
-(12x+7x)+(60+21)=5
-19x+81=5
81-5=19x
76=19x
x=76:19=4
vậy x=4
c) 2x2-3=29
2x2=29+3=32
x2=32:2=16
x=4 hoặc x=-4
vậy x=4 hoặcx=-4
tìm số nguyên x,biết:
A,-4/7=x/21
B.(x-3)/15=1/-5
C.(3x+8)/-12=-5/30
Tính:
a) 16/15 . -5/14 . 54/24 . 56/21
b)7/3 . -5/2 . 15/21 . 4/-5
c)( -2/5 + 1/3) . ( 3/2 - 3/7)
d)(1/2 - 1/3) . ( 5 - 1/4)
e) ( 4/5)^2
a) 2x - 261 = -21
b) 15 . (-2) - x = 45
c) -18 + ( 7 - x)^2 = -2
d) ( 2x - 1 ) chia hết ( x +1)
/x-2/=3*x /x-3/-7=13 72-(43-/x/)=45
3*/x-1/-5=7 (7-x )*(x+9)=0 (x-2)*(x+15)=0
-12*(x-5)+7*(3-x)=5 2x^2-3=29
Tìm x, biết
a) 3 1/3x+16 3/4= -13,25 b) (2 4/5x-50) :2/3=51 c) |2x-1|=(-4)2 d)x+2/5=-11/15
e) (x-7/18).18/29=-12/29
1) -12 (x-5) +7(3-x)=5
2) (x-2). (x+4)=0
3) ( x-2) .( x+15) =0
4) (7-x) .(x+19)=0
5)-5,x,1
6) / x/<3
7)(x-3) (x-5)<0
8)2x2-3=29
Các bạn giải giúp mình nhé.BuingBuing
Tìm x
a) x - 2 + 7 = 1 . 3 . -9
b) 4 . x - 1 = (-5) 5 12 2 4 16 9 2 9
c) -2 . x + 5 = 7
d) 2 . x : 7 . 1 = 29 3 8 12 5 3 8 15
Bài 1: Tìm x:
a) x - 2 + 7 = 1 . 3 . -9
b) 4 . x - 1 = (-5) 5 12 2 4 16 9 2 9
c) -2 . x + 5 = 7
d) 2 . x : 7 . 1 = 29 3 8 12 5 3 8 15
a)-5.(-x+7)-3.(-x-5)=-4.(12-x)+48
b) (-x-7)-5.(-x-3)=12.(3-x)
c)-2.(15-3x)-4.(7x+8)=-5-9.(-2x+1)
d) (-3x-7) - 4.(-2x-11)=7.(4x+10)+9
