Question

of x-3 is a factor of x square -kx+12 then find the value if k also find the other factor of the polynomial for this value k

Answer 1

Step-by-step explanation:

$x {}^{2} - kx + 12 = 0$

Given that (x–3) is a factor

Therefore if we put x,=3 in above equation we should get zero

$3 {}^{2} - k(3) + 12 = 0\\ 9 - 3k + 12 = 0\\ 21 - 3k = 0 \\ 3k = 21 \\ k = 21 \div 3 \\ k = 7$

Now equation becomes

${x}^{2} - 7k + 12$

$x {}^{2} - 4k - 3k + 12 = 0 \\ x ( x - 4) - 3(x - 4) = 0 \\ (x - 3)(x - 4) = 0$

Hence other factor

x = 3