tim x biet
8+3.X=68
tim x va y biet
a)x/18=y/15 va x-y=-30
b)7*x=9*y va 10*x-8*y=68
c)(x1/2)^50 +(y+1/3)^40=o
a)
\(\frac{x}{18}=\frac{y}{15},x-y=-30\)
\(\frac{x}{18}=\frac{y}{15}\)
\(\frac{x}{18}-\frac{y}{15}=0\)
\(-\frac{6y-5x}{90}=0\)
\(6y-5x=0\)
\(x-y=-30\)
\(-\left(y-x-30\right)=0\)
\(y-x-30=0\)
\(\Rightarrow x=-180;y=-150\)
dẫn tui bài y:9-8=15 với
tim x biet : /x+5/+/3-x/=8
De tim so tu nhien x ,biet rang neu lay so do tru di 3 roi chia cho 8 thi dc 12 ,ta co the viet (x-3) :8=12roi tim x , ta duoc x =99.
Bang cach lam nhu tren ,hay tim so tu nhien x,biet rang neu no nhan voi 3 roi tru di 8 ,sau do chia cho 4 thi dc 7
tim x biet x + 3 = 8
ta có:
x+3=8
=>x=8-3
=>x=5
Vậy x=5
tim x nguyen duong biet 1/x(x+3)+1/(x+3)(x+6)=3/8
3) tim so tu nhien x biet
a) 450 : (3-19 )=50
b )3^2 x( x +4 ) -5^2 =5x 2^2
c )7x = 511: 5^9 +3^1
d) 6x =68 -2^ 19 :2^16
a/\(450:\left(x-19\right)=50\)
=>\(x-19=9\)
=>\(x=28\)
Vậy...
b/\(3^2.\left(x+4\right)-5^2=5x.2^2\)
\(9\left(x+4\right)=20x+25\)
\(20x+25=9x-36\)
\(11x=-61\)
\(x=-\dfrac{61}{11}\)
Vậy..
c/Tương tự
d/Tương tự
tim x biet (2.|x|+3).4-8=|-20|
( |x| . 2 + 3).4-8 = 20
( |x| . 2 + 3).4 = 20 + 8
|x| . 2 + 3 = 28 : 4
|x| . 2 = 7 - 3
|x| . 2 = 4
|x| = 4 : 2
|x| = 2
\(\Rightarrow\) x = 2 hoặc -2
Tim x, biet : 5/4 nhan x = 5/8 + 3/12
tim x,y thuoc N biet (x-6).(2y+3)=8