Question

find the value of m and n if the polynomial 2x^3+mx^2+nx-14 has x-1 and x+2 as its factors​

Answer 1

Answer:

Since x- 1 is its factor

so

$2( {1)}^{3} + m {1}^{2} + n - 14 = 0 \\ 2 + m + n - 14 = 0 \\ m + n = 12 \\ n = 12 - m$

Since x + 2 is its factor

so

$2( { - 2)}^{ 3} + m {( - 2)}^{2} - 2n - 14 = 0 \\ - 16 + 4m - 2(12 - m) - 14 = 0 \\ - 30 + 4m - 24 + 2m = 0 \\ 6m = 54 \\ m = 9 \\ so \: n \: = 3$

Answer 2

Answer:

this is correct............................