A quick look at the Quadratic Formula gives both answers. Write the two solutions separately and you will see it.
It's the same as what Plato has done, really - but I'll try to explain it a bit more. (I'm new here, and I don't mean to 'trump' anyone else's answer - so if this is unacceptable, please let me know. Thanks. )
If the roots of are ,
Think about what you're doing when you solve a quadratic, and then just do the reverse....
must be the same equation.
Divide equation (A) by a, so it becomes
Then compare coefficients:
Original Problem Statements (Emphasis Added)
"Show that the sum of the two solutions of this equaion is -(b/a)"
"show that the product of the two solutions of this equation is c/a"
"Sum" is addition. "Product" is multiplication.
Original Reply: "A quick look at the Quadratic Formula gives both answers. Write the two solutions separately and you will see it."
Have you done this, yet?
Write them down. Add them. What is the result?
Write them down again. Myltiply them. What is the result?