Answer:
k = -9
Step-by-step explanation:
f(x) = 2x²+kx-20
From remainder theorem,
x = 10 and f(10) = 90
f(10) = 90
Subsitute the value of x into the expression above.
f(10) = 2(10²)+10k-20 = 90
200+10k-20 = 90
Solve for k by collecting like terms
10 k = 90+20-200
10k = 110-200
10k = -90
k = -90/10
k = -9.
Hence the value of the constant is -9
