## anonymous 4 years ago 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

1. anonymous

2. anonymous

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

3. anonymous

Alright then, the floor is yours lol

4. anonymous

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 $r_1r_2=\frac{c}{a}$

5. anonymous

*product

6. anonymous

7. anonymous

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

8. anonymous

sum is -4/7

9. anonymous

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

10. anonymous

Thank you so much

11. anonymous

could you explain how did you get the A .