Question

x^2-8x+_?and also x^2-3x+_?

Answer 1

Step 1

Write out an equation that will make a quadratic equation a perfect square.

$b^2\text{ = 4ac}$$\begin{gathered} In\text{ this} \\ x^2\text{ - 8x + c} \\ a\text{ = 1 , b = -8 and c = ?} \\ b^2\text{ = 4ac} \\ (-8)^2\text{ = 4 x 1 x c} \\ 64\text{ = 4c} \\ c\text{ = 64/4} \\ c\text{ = 16} \end{gathered}$

$\begin{gathered} x^2\text{ - 3x + c} \\ a\text{ = 1} \\ b\text{ = -3} \\ c\text{ = ?} \\ b^2\text{ = 4ac} \\ (-3)^2\text{ = 4 x 1 x c} \\ 9\text{ = 4c} \\ c\text{ = 9/4} \end{gathered}$