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Unformatted text preview: gebra Example 2 Solve each of the following equations.
(a) 7 x = 9 [Solution]
(b) 2 4 y +1 - 3 y = 0 [Solution]
(c) et + 6 = 2 [Solution]
(d) 105- x = 8 [Solution]
(e) 5e 2 z + 4 - 8 = 0 [Solution]
(a) 7 x = 9
Okay, so we say above that if we had a logarithm in front the left side we could get the x out of
the exponent. That’s easy enough to do. We’ll just put a logarithm in front of the left side.
However, if we put a logarithm there we also must put a logarithm in front of the right side. This
is commonly referred to as taking the logarithm of both sides.
We can use any logarithm that we’d like to so let’s try the natural logarithm. ln 7 x = ln 9
x ln 7 = ln 9
Now, we need to solve for x. This is easier than it looks. If we had 7 x = 9 then we could all
solve for x simply by dividing both sides by 7. It works in exactly the same manner here. Both
ln7 and ln9 are just numbers. Admittedly, it would take a calculator to determine just what those
numbers are, but they are numbers and so we c...
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This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.
- Spring '12