Question

find the sum of zeroes of the polynomial x^2-3x-m (m+3).​

Answer 1

Step-by-step explanation:

f(x) = x2 – 3x – m (m + 3)

By adding and subtracting mx,

f(x) = x2 – mx – 3x + mx – m (m + 3)

= x[x – (m + 3)] + m[x – (m + 3)]

= [x – (m + 3)] (x + m)

f(x) = 0 ⇒ [x – (m + 3)] (x + m) = 0

⇒ [x – (m + 3)] = 0 or (x + m) = 0

⇒ x = m + 3 or x = –m

So, the zeroes of f(x) are –m and +3.