How do you solve $x^2-7x+8=0$ using the quadratic formula?

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Answer 1 · 2018-03-27T13:45:37

$color(blue)(x=7/2+sqrt(17)/2$

$color(blue)(x=7/2-sqrt(17)/2$

For quadratics in the form:

$color(red)(ax^2+bx+c)$

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

We have:

$bba = 1$

$bb(b)=-7$

$bbc=8$

Plugging these into the formula:

$x=(-(-7)+-sqrt((-7)^2-4(1)(8)))/(2(1))$

$x=(7+-sqrt(49-32))/(2)$

$x=(7+-sqrt(17))/(2)$

$color(blue)(x=7/2+sqrt(17)/2$

$color(blue)(x=7/2-sqrt(17)/2$

How do you solve x^2-7x+8=0x^2-7x+8=0 using the quadratic formula?