Tìm x,y,z biết :

1) \(x:y:z=3:5:\left(-2\right)\) và \(5x-y+3z=-16\)

2) \(\dfrac{x}{2}=\dfrac{y}{-3};\dfrac{z}{3}=\dfrac{y}{4}\) và \(x+y+z=5,2\)

3) \(2x=3y;7z=5y\) và \(3x-7y+5z=30\)

4) \(3x=4y=5z\) và \(x-\left(y+z\right)=-21\)

5) \(\dfrac{x-1}{2}=\dfrac{y-2}{3}=\dfrac{z-3}{4}\) và \(2x+3y-z=50\)

Tìm x, biết:

a) \(\left(5x+1\right)^2=\dfrac{36}{49}\)

b) \(\left[\left(-0,5\right)^3\right]^x=\dfrac{1}{64}\)

c) \(2020^{\left(x-2\right).\left(2x+3\right)}=1\)

d) \(\left(x+1\right)^{x+10}=\left(x+1\right)^{x+4}\) với \(x\in Z\)

e) \(\dfrac{3}{4}\sqrt{x}-\dfrac{1}{2}=\dfrac{1}{3}\)