How do you find the roots, real and imaginary, of y=x^2-5x + 6 using the quadratic formula?

2 Answers
Mar 26, 2017

x in {2,3}

Explanation:

The quadratic formula works for equations of the form:

y = ax^2 + bx + c

And states that the solutions for x are:

x = (-b+-sqrt(b^2-4ac))/(2a)

In this case, the quadratic equation is y = x^2 - 5x + 6, so:

a = 1
b = -5
c = 6

So, just plug these values into the quadratic equation and simplify.

x = (-b+-sqrt(b^2-4ac))/(2a)

x = (-(-5)+-sqrt((-5)^2-4(1)(6)))/(2(1))

x = (5+-sqrt(25-24))/2

x = (5+-sqrt1)/2

x = (5-1)/2 color(white)"XX" or color(white)"XX" x = (5+1)/2

x = 2 color(white)"XX" or color(white)"XX" x = 3

Therefore, the solutions to this quadratic are x=2 and x=3. You can write this any way that you like (or whichever way your teacher prefers), but a common way to write it is like this, using set notation:

x in {2,3}

This just means that x could be any number in the set {2,3} to make the equation true.

Final Answer

Mar 26, 2017

x=2" or " x=3

Explanation:

The standard form of a quadratic function is.

• y=ax^2+bx+c ; a!=0

"For " y=x^2-5x+6

rArra=1,b=-5" and " c=6

Using the color(blue)"quadratic formula"

color(red)(bar(ul(|color(white)(2/2)color(black)(x=(-b+-sqrt(b^2-4ac))/(2a))color(white)(2/2)|)))

rArrx=(-(color(red)(-5))+-sqrt(25-(4xx1xx6)))/2

color(white)(rArrx)=(5+-sqrt1)/2

rArrx_1=(5+1)/2" or " x_2=(5-1)/2

rArr" roots are " x_1=3" or " x_2=2

Both roots are real. There are no imaginary roots.