

Given, the polynomial 6x4 + 8x3 - 5x2 + ax + b is exactly divisible by polynomial 2x2 - 5
So, the remainder should be zero.
Now,

Since the remainder should be zero
=> (20 + a)x + 25 + b = 0
Now, the coefficient of x and constant term both should be equal to zero
=> 20 + a = 0
=> a = -20
and 25 + b = 0
=> b = -25
So, the value of and b are -20 and -25 respectively.
