Reply to Thread New Thread 
08152012, 12:20 AM  #1 

I'm stuck.
I'm to factorise z^2 + 14zy + 49y^2 and the answer is (z + 7y)^2 and is a perfect square. I can see that z is the square root of z^2 and that 7y is the square root of 49y^2 but I don't understand how I'm meant to look at it and know that it's a perfect square. I suppose if I could do that, I would know how to factorise it. given that the perfect square factoring formula (?) is x^2 + 2xy + y^2 = (x + y)^2 what am I looking for/at? 

08152012, 12:34 AM  #3 



08152012, 12:42 AM  #6 

ok ok I think I'm seeing it Morrie It's simple enough I think to see that 36 and 49 are both squares, yeah? That's the first clue. Then just see if/how the square roots of those can fit in with the middle term. 84ab = 2*42ab = 2*6*7*ab =2*6a*7b 

08152012, 05:39 AM  #8 



Reply to Thread New Thread 
Thread Tools  
Display Modes  
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)  
