Here are my answers. Can you check if I got the right answers? Thank you!

Solve for z:

4x+10yx=0
z=-2x/5y

y^2+3yz-8z-4x=0
z=(-y^2+4x)/(3y-8)

there was no z in your first equation, from you answer I can tell it should have been 4x + 10yz = 0
If so, the answer is right.

last one is right

To solve the equation 4x + 10yx = 0, let's check if the answer z = -2x/5y is correct.

To verify this, we substitute the value of z back into the equation and simplify:

4x + 10yx = 0

4x + 10y(-2x/5y) = 0

4x - 4x = 0

Since both sides of the equation cancel out, we can conclude that z = -2x/5y is the correct solution for the given equation.

Now, let's move on to the second equation: y^2 + 3yz - 8z - 4x = 0.

To check if the answer z = (-y^2 + 4x)/(3y - 8) is correct, we substitute the value of z back into the equation and simplify:

y^2 + 3y((-y^2 + 4x)/(3y - 8)) - 8((-y^2 + 4x)/(3y - 8)) - 4x = 0

Simplifying, we get:

y^2 - 3y^3/(3y - 8) + 8y^2 - 32x/(3y - 8) - 4x = 0

To further simplify, we need to find a common denominator for the fractions:

(y^2(3y - 8) - 3y^3 + 8y^2(3y - 8) - 32x)/(3y - 8) - 4x = 0

Expanding and combining similar terms, we have:

(3y^3 - 8y^2 - 3y^3 + 24y^2 - 32x)/(3y - 8) - 4x = 0

Simplifying further, we get:

(16y^2 - 32x)/(3y - 8) - 4x = 0

Since both sides are not equal, we can conclude that z = (-y^2 + 4x)/(3y - 8) is not the correct solution for the given equation.

Please double-check the calculations to find the correct solution for the second equation.