Tìm x biết :
|x-5|+|5-x|=3
a)tìm x biết: 5^x-1 + 5^x-3= 650
b)tìm x biết: gttd x+1 +gttd x+2 +.......+gttd x+100=605x (gttd: giá trị tuyệt đối)
c) tìm x,y biết : (2x+1)/5=(4y-5)/9=(2x+4y-4)/7x
a) \(5^{x-1}+5^{x-3}=650\)
\(\Rightarrow5^x\left(\frac{1}{5}+\frac{1}{125}\right)=650\)
\(\Rightarrow5^x=650:\frac{26}{125}\)
\(\Rightarrow5^x=3125\)
\(\Rightarrow5^x=5^5\)
\(\Rightarrow x=5\)
Tìm x biết :
x x 5 + x : 5 = x + 3/5
Ai giúp mình với
`x xx 5 + x :5 =x+3/5`
`=> x xx 5 + x xx 1/5=x+3/5`
`=> x xx (5+1/5) =x+3/5`
`= x =x+3/5`
`=> x-x=3/5`
`=> 0=3/5(ko. t/m)`
Tìm x biết 3(x-1/2)-5(x+3/5)=1/5-x
(5x + 3) (x - 4) - (x - 5) x = (2x - 5) (5 + 2x)
Tìm x biết
\(\Leftrightarrow5x^2-20x+3x-12-x^2+5x=4x^2-25\)
\(\Leftrightarrow-18x=-13\)
hay x=13/18
Tìm stn x biết:5^(x-1)+5^(x-2)+5^(x-3)=775
\(5^{x-1}+5^{x-2}+5^{x-3}=775\\ 5^{x-3}.\left(25+5+1\right)=775\\ 5^{x-3}.31=775\\ 5^{x-3}=\dfrac{775}{31}=25=5^2\\ x-3=2\\ x=5\)
Tìm x, biết:
3(x-1/2)-5(x+3/5)= -x+1/5
Tìm x biết
-5(x+1/5)-1/2(x-2/3)=3/2x-5/6
3(x-1/2)-5(x+3/5)=-x+1/5
bài 1 :tìm x , biết :
(x-7)^ x+1(x-7)^x+11=0
bài 2 :tìm x , biết :
a,|2x-3| > 5 c,|3x-1| ≤ 7 d,|3x-5| + |2x+3| = 7
bài 3 :
a,tính tổng S = 1 + 5^2 + 5^4 + ....... + 5^200.
b,so sánh 2^30 + 3^30 + 4^30 và 3.24^10
Tìm x,biết:
a)-5×(x+1/5)-1/2×(x-2/3)=3/2x-5/6
b)3×(x-1/2)-5(x+3/5)=-x+1/5
Tìm x biết
X-3/x+5=5/7
\(đk:x\ne-5\\ \dfrac{x-3}{x+5}=\dfrac{5}{7}\\ =>7\left(x-3\right)=5.\left(x+5\right)\\ =>7x-21=5x+25\\ =>7x-5x=25+21\\ =>2x=46\\ =>x=23\left(t/m\right)\)
\(\dfrac{x-3}{x+5}=\dfrac{5}{7}\left(x\ne-5\right)\)
\(\Rightarrow7\left(x-3\right)=5\left(x+5\right)\)
\(\Rightarrow7x-21=5x+25\)
\(\Rightarrow7x-21-5x-25=0\)
\(7x-5x-21-25=0\)
\(2x-46=0\)
\(2x=0+46=46\)
\(x=\dfrac{46}{2}=23\left(tmđk\right)\)