Friday

August 22, 2014

August 22, 2014

Posted by **Amy** on Thursday, January 27, 2011 at 5:20pm.

2^(2x) + 2^(x) -12 = 0

Steps too

I tried solving this but I ended with ln(12) / 2ln(2) + ln(2) but the real answer is supposed to be ln(3) / ln(2) or 1.585

- Precalc -
**Reiny**, Thursday, January 27, 2011 at 5:39pmlet 2^x= y

then your equation becomes

y^2 + y - 12 = 0

(y+4)(y-3) = 0

so y = -4 or y = 3

then

2^x= -4, which is not possible

or

2^x = 3

ln both sides

ln(2x) = ln3

x ln2 = ln 3

x = ln3/ln2 = appr. 1.58

**Related Questions**

Precalc - how to write each expression into a single logarithm. ln(x-1/x) + ln(...

Calculus - Evaluate (integral) cot 2x dx. A. 1/2Ln sin 2x+C B. 1/2Ln cos 2x+C C...

Precalc - Solve for x log[1/3](x^(2) + x) - log[1/3] (x^(2) - x) = -1 Steps too ...

Precalc - Solve for x log[1/3](x^(2) + x) - log[1/3] (x^(2) - x) = -1 Steps too ...

Precalc, i really don't get my hw - how do i do this? factor x^4-x^2-20 over ...

Precalc - (2^(x))(5)=10^(x) steps too please how to solve

Precalc - There's f(x) = (2x+3)/(x+4) and g(x) = (4x-3)/(2-x) Solve for x in f(g...

Precalc - how to solve 5(2^(3x)) = 8 Steps too please answer is ln 1.6 / 3 ln 2

Precalc - how to solve for x: 500e^(0.3x) = 600 Steps please.

Calculus - How do I solve for lim h->0 (((a+h)^2 + 1)/(3(a+h)+7) - ((a^2 + 1...