Help !!!!! Can anyone tell me if this is correct?
Im trying to find the zeros of the function but none of the possible rational roots come out to zero in my equation im suposed to use synthetic division to get the the first zero then use the quadratic formula to find tthe rest but none of the possible rational roots come out to zero so I figured I messed up when i turned the lenth width and hieght into a polynomial.

V = L*W*H 105 = 7* 5* 3105 = x * (x - 2) * (x - 4)
4) Now it’s time to simplify and write the equation in standard form!
a. Show your work below as you write your equation in standard form.
i. Use distributive property to multiply. 105 = x2 - 2x(x - 4)
105 = x3 - 4x2 - 2x2 - 8x105 = x3 - 6x2 - 8x
ii. As your last step, subtract the number for volume from both sides so you have 0 on the left in your final answer

Question

Help !!!!! Can anyone tell me if this is correct?
Im trying to find the zeros of the function but none of the possible rational roots come out to zero in my equation im suposed to use synthetic division to get the the first zero then use the quadratic formula to find tthe rest but none of the possible rational roots come out to zero so I figured I messed up when i turned the lenth width and hieght into a polynomial.
 
V = L*W*H 105 = 7* 5* 3105 = x * (x - 2) * (x - 4) 
4) Now it’s time to simplify and write the equation in standard form! 
a. Show your work below as you write your equation in standard form. 
i. Use distributive property to multiply. 105 = x2 - 2x(x - 4)
 105 = x3 - 4x2 - 2x2 - 8x105 = x3 - 6x2 - 8x
ii. As your last step, subtract the number for volume from both sides so you have 0 on the left in your final answer