tim x
880-x.8=80
cho x/4=y/5.tim x y biet a) x+y=54 b) 3x -2y=8 c) x.y=80
Tim x biet
A, x/15 = x-2/30
B, 7/8 < x/80 < 9/10
C, 1/6 < 5/x < 1/4
a) \(\dfrac{x}{15}\)=\(\dfrac{x-2}{30}\)
=>30x=15 (x-2)
=>30x=15x-30
=>30x-15x=-30
=>15x =-30
=>x =-2
b)\(\dfrac{7}{8}\)<\(\dfrac{x}{80}\)<\(\dfrac{9}{10}\)
=>\(\dfrac{70}{80}\)<\(\dfrac{x}{80}\)<\(\dfrac{72}{80}\)
=> 70<x<72
=>x=71
c)\(\dfrac{1}{6}\)<\(\dfrac{5}{x}\)<\(\dfrac{1}{4}\)
=>\(\dfrac{5}{30}\)<\(\dfrac{5}{x}\)<\(\dfrac{5}{20}\)
=>20<x<30
=>x={21;22;23;24;25;26;27;28;29}
tim x thuoc z
a) (x2+8).(x2-6).(x2+80)< 0
b)/x/+/-x+3/ =7 với 0<x<3
tim x va y biết y ^ 2 = 80 + 33 ^ x
tim x
100-(x:5+3/2)=80
100 - ( x : 5 +3/2 ) = 80
<=> x : 5 + 3/2 = 100 - 80
<=> x : 5 + 3/2 = 20
<=> x : 5 = 37/2
<=> x = 185/2
Vậy _
100- (x:5+3/2)=80
=> x:5 + 3/2 = 100-80
=> x:5 + 3/2 = 20
=> x:5 = 20- 3/2
=>x:5 = 37/2
=> x =185/2
Vậy x = 185/2
3*(X-4)-66=4x-80.Tim x thuộc N
tim x
100-(x:5+3/2)=80
\(100-\left(\frac{x}{5}+\frac{3}{2}\right)=80\)
\(\frac{x}{5}+\frac{3}{2}=20\)
\(\frac{x}{5}=18,5\)
\(x=92,5\)
x:5+3/2= 100-80
x:5+3/2=20
x:5=20-3/2
x:5=37/2
x= 37/2x5
x=185/2
100 - ( x : 5 + \(\frac{3}{2}\)) = 80
( x : 5 + \(\frac{3}{2}\)) = 100 - 80
( x : 5 + \(\frac{3}{2}\)) = 20
( x : 5) = 20 - \(\frac{3}{2}\)
( x : 5) = 18,5
x = 18,5 x 5
x = 92,5
Vậy x = 92,5
tim x,y
2^x + 80 = 3^y
\(2^x+80=3^y\)(1)
Nếu x > 0 thì Vế trái (1) chẵn không bằng Vê phải (1) lẻ được. Loại=> x = 0 thì (1) \(\Leftrightarrow2^0+80=3^y\Leftrightarrow3^y=81\Leftrightarrow y=4\)PT có nghiệm (x=0; y=4).
Tim x:
4^x+1 +4^x =80