Put y=0 and obtian the values of x
divd both sides by 2
add one on both sides
do other similarly
The discriminant is less than 0 which means that it does not cross the x-axis hence you won't have x-intercepts.
Try the other equation yourself by checking the discriminant for the nature of the curve. If it's greater than or equal to zero then it will have x-intercepts. To find it, make y equal to 0 and solve for x.
For quadratic equations in the form:
The general rule to completing the square is:
Use this rule to complete the square for your equations.