solving quadratic equations by factoring

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latresa31s

Junior Member
Joined
Sep 4, 2005
Messages
135
ok I got stuck when I started this problem.

4x^2 + 10x + 25 = 30x
-30x -30x

4x^2 - 20x + 25 = 0 And then I am stuck

Can't seem to figure out what is next.
 
latresa31s said:
ok I got stuck when I started this problem.
4x^2 + 10x + 25 = 30x
-30x -30x
4x^2 - 20x + 25 = 0 And then I am stuck
Can't seem to figure out what is next.
Click to expand...
Since we have 4x^2 (2^2 = 4) and 25 (5^5 = 25), we could be lucky; try:
(2x - 5)(2x - 5)
Does it work?
 
latresa31s said:
I got 2 1/2 I know it is wrong but could you work the problem for me
Click to expand...
Why do you think 2 1/2 is wrong? Substitute it in the equation:
4x^2 - 20x + 25 = 0
4(2.5)^2 - 20(2.5) + 25 = 0
4(6.25) - 50 + 25 = 0
25 - 50 + 25 = 0
50 - 50 = 0
 
latresa31s said:
Thanks I did not try to check it I just figured it to be wrong
Click to expand...
WHY? if 2x - 5 = 0, then 2x = 5, x = 5/2 : capish?
 
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