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The roots of the equation (x – 1)(x + k) = - 4 are equal. Find the values of k.

ZKhan158

(x – 1)(x + k) = - 4

Reply 1

jack3473

Original post by ZKhan158

(x – 1)(x + k) = - 4

Expand the brackets, move the -4 across to the other side, use the discriminant b^2-4ac and set it equal to zero as it is a repeated root.

This should leave you with an equation you can solve for k.

I've not actually done the question, this is just my first hunch.

(edited 5 years ago)

Reply 2

Marmeat

Original post by Jackudy3

Expand the brackets, move the -4 across to the other side, use the discriminant, b^2-4ac and solve it equal to zero as it is a repeated root.

This should leave you with an equation you can solve for k.

I've not actually done the question, this is just my first hunch.

I do believe this is correct.

Reply 3

jack3473

Original post by ZKhan158

(x – 1)(x + k) = - 4

Hint: When you expand and move the four across to the other side, remember that there must be only one 'thing' as the coefficient of the x term... perhaps you can factorise?