Question 300046
 how do I solve log base 2 of 20?
Solve it for what?  There's no variable, and it's not an equation.
You can evalute it, or calculate it.
{{{log(2,20) = log(20)/log(2)}}}
=~ 4.321928
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log base 2 (x to the 3rd + 2x)= 3? I solve it on a quiz but it was incorrect here's what I did)
{{{log(2,(x^3 + 2x)) = 3}}}
{{{x^3 + 2x = 8}}}
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If it's actually x^2:
{{{x^2 + 2x - 8 = 0}}}
(x+4)*(x-2) = 0
x = -4, 2
-4 won't work, it gives the log of a negative number
x = 2
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x sq + 2x - 3 = 0
(x - 2)(x + 1)= 0
x - 2 = 0 x + 1 =0 
x=2 x= -1