BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

What am I missing?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 6
Joined: Sun Aug 03, 2008 10:21 am

What am I missing?

by nickp33 » Fri Oct 10, 2008 1:21 pm
I have been prepairing for the GMAT for the past few months and I was working through practice problems in the GMAT Review 11th edition. Factoring is one of my weak points, so I try to concentrate on that area. Here is a practice problem I am having trouble with. I get it to the 3rd step and I can not in my life figure how they go from step 3 to 4. Once I'm at step 4, there is no problem, but I'm stuck between 3 and 4. Can someone please explain?
Thanks!

x^3-2x^2+x = -5(x-1)^2

Step 1: x^3-2x^2+x+5(x-1)^2=0
Step 2: x(x^2+2x+1)+5(x-1)2=0
Step 3: x(x-1)^2+5(x-1)^2=0
Here is where I get lost!
Step 4: (x+5)(x-1)^2=0
Step 5: X= -5 or X=1
Top
Source: — Problem Solving |
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Fri Oct 10, 2008 1:38 pm
Corrected step2 in bold and explained step4

Step 1: x^3-2x^2+x+5(x-1)^2=0

Step 2: x(x^2-2x+1)+5(x-1)^2=0

Step 3: x(x-1)^2+5(x-1)^2=0

Here is where I get lost!
Step 4: (x+5)(x-1)^2=0

Step 5: X= -5 or X=1

From step3 to step4 you can take the common factor (x-1) ^ 2
Therefore step4 is (x-1) ^ 2 (x+5)


Hope this helps!
Top
Legendary Member
Posts: 833
Joined: Mon Aug 04, 2008 1:56 am
Thanked: 13 times

by vivek.kapoor83 » Sat Oct 11, 2008 12:14 am
taking factors..it pretty easy.pls use the same method as u take common in quad. equation
Top
Legendary Member
Posts: 574
Joined: Sun Jun 01, 2008 8:48 am
Location: Bangalore
Thanked: 28 times

by vishubn » Sat Oct 11, 2008 6:18 am
Factors !!
Step 1: x^3-2x^2+x+5(x-1)^2=0
Step 2: x(x^2+2x+1)+5(x-1)2=0
Step 3: x(x-1)^2+5(x-1)^2=0
Here is where I get lost!
Step 4: (x+5)(x-1)^2=0
Step 5: X= -5 or X=1
in step3 u came to the point where us see (x-1)^2 with different co efficients

so we know (x-1)^2 is common !

so (x-1)^2 (x+5) .... if u still confused ! ( multiply this line .. u get back to step 2)

Vishu
Top
Post new topic Post Reply
• Page 1 of 1