Question

Find the value of a if $2 x^3 - 6 x^2 + 5 ax - 9$ leaves the remainder $13$ when it is divided by $x - 2$.

Answer 1

put x = 2 in given equation 
2(2³)  - 6(2²) + 5*a*2 - 9 = 13
16 - 24 + 10a - 9 = 13
10a = 30
a = 3