one way is to sub those values for x
when x=2, z(x)=35
35=6(2)³+b(2)²-52(2)+15
35=48+4b-104+15
35=4b-41
add 41 to both sides
76=4b
divide by 4
19=b
z(x)=6x³+19x²-52x+15
and z(-5)=0
that means (x+5) is a factor
divide using synthetic division or something
(6x³+19x²-52x+15)/(x+5)=6x²-11x+3
factor
6x²-11x+3=(2x-3)(3x-1)
set each to zero
2x-3=0
2x=3
x=3/2
3x-1=0
3x=1
x=1/3
th zeroes are at x=-5, 1/3, 2/3
