Question

If x^2 - x - 42 = (x + k) (x + 6) then the value of k is​

Answer 1

Answer:

-7

Step-by-step explanation:

1. x^2-x-42=0
2. x^2-7x+6x-42=0
3. x(x-7)+6(x-7)=0
4. (x-7)(x+6)=x^2-x-42
5. (x-7)(x+6)=(x+k)(x+6)
6. k=-7

Answer 2

Answer:

We can solve it easily by applying the method of splitting the middle term on the left hand side of the equation after that can we compare both sides of equation then we will get the value of k

As given below:-

LHS:-

${x}^{2} - x - 42 \\ = {x}^{2} - 7x + 6x - 42 \\ = x(x - 7) + 6(x - 7) \\ = (x - 7)(x + 6)$

now when we compare it with right hand side of the equation we get :-

$(x - 7)(x + 6) = (x + k)(x + 6)$

$\implies \: k = - 7 \: \:\underline{ \: \underline{(answer )}}$