Question

(x+1) is a factor of x² + 9x² + 7x² +9ax+5a^2
then find the value of a.​

Answer 1

Remember this : If x+a is a factor of f(x) then f(-a) = 0.

Given x +1 is a factor of x² + 9x² + 7x² + 9ax + 5a² = 17x² + 9ax + 5a² let it be g(x).

Now g(-1) = 0

i.e 17 -9a + 5a² =0,

Now use the quadratic formula -b ±√(b² - 4ac)/2a and solve for a.