Question

please show the work on how to solve x(x-8)=5?

Answer 1

you can use quadratic equation

Answer 2

\[x(x-8)=5 \Longrightarrow x^{2}-8x=5 \Longrightarrow x^{2}-8x-5=0\]
then use quadratic formula

Answer 3

I am not sure how to use the quadratic formula

Answer 4

\[{-b \pm \sqrt{b^2-4ac}}\over{2a}\]

Answer 5

ax^2+bx+c

Answer 6

so this is my answer?

Answer 7

no, this is not the final answer....

from the equation found by joemath, for your question a = 1, b = -8 and c = -5

also imranmeah has given the formula according to which

- (-8) +/- root[(-8)^2 - 4(1)(-5) 8 +/- root[64 + 20] 8 +/- root(84)
so x = ----------------------------- = ------------------- = ---------------
2 * 1 2 2

8 +/- 2root(21) 2 [4 +/- root(21)]
x = --------------- = -----------------
2 2

so two value of x are

\[4 + \sqrt{21} and 4-\sqrt{21}\]