Question

if (x-2) is a factor of 2x³ - Kx²-8 x + 20
Find the value of k
with the value of x, factorise the above expresion completely​

Answer 1

$let \: (x-2) = 0 \\ x = 2 \\ 2x³ - Kx²-8 x + 20 = 0 \\ keep \: the \: value \: of \: (x) \\ 2 \times {2}^{3} - k {2}^{2} - 8 \times 2 + 20 = 0 \\ 16 - k {2}^{2} - 16 + 20 = 0 \\ - k {2}^{2} + 20 = 0 \\ k {2}^2 = 20 \\ k \times 4 = 20 \\ k = \frac{20}{5} \\{ \bold{ \red{ \ k = 5}}}$

${\huge\mathcal{\fcolorbox{lime}{black}{\pink{FROM☞ ADESH \: KUMAR}}}}$

Answer 2

Answer:

5

Step-by-step explanation:

Given, (x-2) is a factor

∴ x-2=0

x=2

put the value of x=2 in 2x³-Kx²-8x+20

   2x³-Kx²-8x+20=0

⇒ 2×2³-K×2²-8×2+20 =0

⇒ 2×8-K×4-16+20=0

⇒16-4K-16+20=0

⇒4K=20

∴ K=5