Get clear, concise, and accurate answers to your questions on IDNLearn.com. Our platform is designed to provide quick and accurate answers to any questions you may have.

given that alpha and beta are roots of the quadratic equation ax²+bx+c=0, show that alpha+beta=-6÷a and alphabeta=c÷a​

Sagot :

Answer:

[tex]\alpha + \beta = -\frac{b}{a}[/tex]

[tex]\alpha \beta = \frac{c}{a}[/tex]

Step-by-step explanation:

Given

[tex]ax^2 + bx + c = 0[/tex]

[tex]Roots: \alpha \& \beta[/tex]

Required

Show that:

[tex]\alpha + \beta = -\frac{b}{a}[/tex]

[tex]\alpha \beta = \frac{c}{a}[/tex]

[tex]ax^2 + bx + c = 0[/tex]

Divide through by a

[tex]\frac{a}{a}x^2 + \frac{b}{a}x + \frac{c}{a} = \frac{0}{a}[/tex]

[tex]x^2 + \frac{b}{a}x + \frac{c}{a} = 0[/tex]

The general form of a quadratic equation is:

[tex]x^2 - (Sum)x + (Product) = 0[/tex]

By comparison, we have:

[tex]-(Sum)x = \frac{b}{a}x[/tex]

[tex]-(Sum) = \frac{b}{a}[/tex]

Sum is calculated as:

[tex]Sum = \alpha + \beta[/tex]

So, we have:

[tex]-(\alpha + \beta) = \frac{b}{a}[/tex]

Divide both sides by -1

[tex]\alpha + \beta = -\frac{b}{a}[/tex]

Similarly;

[tex]Product = \frac{c}{a}[/tex]

Product is calculated as:

[tex]Product = \alpha * \beta[/tex]

So, we have:

[tex]\alpha * \beta = \frac{c}{a}[/tex]

[tex]\alpha \beta = \frac{c}{a}[/tex]