Given f (x) = 7x^2 + 4x - 13, A = sum of roots of f (x) = 0, B = product of roots of f (x) = 0, find ( A + B)^2

Question

Given f (x) = 7x^2 + 4x - 13, A = sum of  roots of f (x) = 0, B = product of roots of f (x) = 0, find ( A + B)^2

anonymous · Answer

Won't factor, use quadratic formula

anonymous · Answer

not to butt in but you can find the sum of the roots and the produce of the roots without finding the roots

anonymous · Answer

Alright then, the floor is yours lol

anonymous · Answer

you can also prove those formulas  using the quadratic formula, but sum of roots of a quadratic 
$$ax^2+bx+c=0$$
$$r_1+r_2=-\frac{b}{a}$$
produce is 
$$r_1r_2=\frac{c}{a}$$

anonymous · Answer

*product

anonymous · Answer

The answer is 289/49. Could you please show me the steps?

anonymous · Answer

product of the roots, according to satellite's formula is -13/7

anonymous · Answer

sum is -4/7

anonymous · Answer

$$(-\frac{13}{7}-\frac{4}{7})^2=(-\frac{17}{7})^2=\frac{289}{49}$$

anonymous · Answer

Thank you so much

anonymous · Answer

could you explain how did you get the A .