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

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Answer 1 · 2018-03-27T13:45:37

$x = \frac{7}{2} + \frac{\sqrt{17}}{2}$ $color(blue)(x=7/2+sqrt(17)/2$

$x = \frac{7}{2} - \frac{\sqrt{17}}{2}$ $color(blue)(x=7/2-sqrt(17)/2$

For quadratics in the form:

$a x^{2} + b x + c$ $color(red)(ax^2+bx+c)$

$x = \frac{- b \pm \sqrt{b^{2} - 4 a c}}{2 a}$ $color(blue)(x=(-b+-sqrt(b^2-4ac))/(2a))$

We have:

$a = 1$ $bba = 1$

$b = - 7$ $bb(b)=-7$

$c = 8$ $bbc=8$

Plugging these into the formula:

$x = \frac{- (- 7) \pm \sqrt{{(- 7)}^{2} - 4 (1) (8)}}{2 (1)}$ $x=(-(-7)+-sqrt((-7)^2-4(1)(8)))/(2(1))$

$x = \frac{7 \pm \sqrt{49 - 32}}{2}$ $x=(7+-sqrt(49-32))/(2)$

$x = \frac{7 \pm \sqrt{17}}{2}$ $x=(7+-sqrt(17))/(2)$

$x = \frac{7}{2} + \frac{\sqrt{17}}{2}$ $color(blue)(x=7/2+sqrt(17)/2$

$x = \frac{7}{2} - \frac{\sqrt{17}}{2}$ $color(blue)(x=7/2-sqrt(17)/2$

How do you solve x^2-7x+8=0x2−7x+8=0x^2-7x+8=0 using the quadratic formula?