tim x
x-1/15=-60/1-x
tim x;y de -xx(2-y)=10 (1-x)x(1+y)=-15
Tim X
a,X - 20/11 x 13 - 20/13 x 15 - 20/15 x 17 -...-20/53 x 55 = 3/11
b,1/21 + 1/28 +1/36 + ... +2/Xx(x + 1) = 2/9
Ta có : A=20/11×13 + 20/13×15 +20/15×17+...+20/53×55
A = 10 ×( 2/11×13+2/13×15+...12/53×55)
A = 10 ×(1/11-1/13+1/13-1/15+1/15-1/17+...+1/53-1/55)
A = 10 × (1/11-1/55)
A =10 × 4/55
A = 8/11
tim 1 phan 2 ; 1 phan 3 ; 1 phan 5 ; 1 phan 6 ; 1 phan 10 ; 1 phan 12 cua 60
tim 15% ; 20%; 50%; 75% cua 60
tim cac so ma 60 chia het cho so do.
tim 1 phan 2 ; 1 phan 3 ; 1 phan 5 ; 1 phan 6 ; 1 phan 10 ; 1 phan 12 cua 60
tim 15% ; 20%; 50%; 75% cua 60
tim cac so ma 60 chia het cho so do.
giúp mình nhanh nha mình đang cần gấp thank
tim nghiem da thuc
3xx+x
xx-5x-6
2xx+10x-12
xxx-xx+x-1
3xx+x = 0
xx-5x-6 = -6
2xx+ 10x -12 = -12
xxx-xx+x -1 =-1
cho $M=\frac{42-x}{x-15}$M=42−xx−15 tim so nguyen x de M dat gia tri nho nhat
tim x, biết x/-15=-60/x
\(\frac{x}{-15}=\frac{-60}{x}\)
=>x.x=(-15).(-60)
=>x2=900=302=(-30)2
=>x=30,-30
Vậy x=30,-30
\(\frac{x}{-15}=\frac{-60}{x}\)
<=> (-15).(-60) = x.x
<=> 900 = x2
=> x2 = 302 = (-30)2
=> x \(\in\){30; -30}
khong biet lam tim a biet 30 + a / 30 = 13 / 15
tim x :-2x-40=(5-x)-(-15+60)
-2x-40=(5-x)-(-15+60)
=> -2x - 40 = 5 - x + 15 +60
=> -2x - 40 = 80 - x
=> -2x + x = 80 + 40
=> -x = 120
-2x-40=(5-x)-(-15+60)
-2x - 40 = 5 - x - 45
-2x - 40 = -x - 40
-2x + x = -40 + 40
-1x = 0
x = 0
3. TINH GIA TRI BIEU THUC SAU VOI X = 1 ,VA Y = 0 :
A, A= ( 15 : X + 15 xX ) + 2009 X Y
B, B= Y : ( 119 xX + 4512 ) + ( 756 : X - Y )
THay `x=1;y=0` vào biểu thức `A` ta có :
`A=(15:1+15xx1)+2990xx0`
`A=(15xx1+15xx1)+2990xx0`
`A=(15xx2)+2990xx0`
`A=30+2990xx0`
`A=30+0=30`
Thay `x=1;y=0` vào biểu thức `B` ta có :
\(B=0:\left(119\times1+4512\right)+\left(756:1-0\right)\\ B=0:4631+756\\ B=0+756=756\)
`a)` Thay `x=1;y=0` vào `A` có:
`A=(15:1+15xx1)+2009xx0`
`A=(15+15)+0=30`
`b)` Thay `x=1;y=0` vào `B` có:
`B=0:(119xx1+4512)+(756:1-0)`
`B=0+(756-0)=756`
a)\(A=\left(15:1+15\times1\right)+2009\times0=30+0=30\)
b)\(B=0:\left(119\times1+4512\right)+\left(756:1-0\right)=0+756=756\)