| Exponents and Radicals |
Solve for x:
4(8x)-21(4x)+21(2x)=4 |
Problem Moderated by: Douglas |
| Problem Solution |
8x=(2x)3, and 4x=(2x)2. Now, if we allow u to equal 2x, we can solve an equation in u:
4u3-21u2+21u-4=0
(4u-1)(u-1)(u-4)=0
u = 2x= 1/4, 1, or 4
x = 0, 2, or -2
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