SOLUTION: I need help with the following: Multiply and then simplify completely: (3√7−5√5)(3√7+5√5) I have come up with several answer and I am having tro

Algebra.Com
Question 1021526: I need help with the following:
Multiply and then simplify completely: (3√7−5√5)(3√7+5√5)
I have come up with several answer and I am having trouble showing my work

Found 2 solutions by ankor@dixie-net.com, josmiceli:
Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
Multiply and then simplify completely:

This FOILs as the difference of squares, the middle terms cancel so we have
9(7) - 25(5) = 63 - 125 = -62

Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!
Let
Let
--------------------

Make this substitution:

---------------------------


and


----------------


------------------
check answer:
I'll do it with calculator:







I assume the error is due to rounding off

RELATED QUESTIONS

Hi,I desperately need help with the following questions: 1. Square root n^2 + 12n +... (answered by jim_thompson5910)
i am asked to multiply (√[3] + 4√[5])(2√[3] –... (answered by checkley77)
Rational and Radical Expressions 1. Simplify the rational expression: x2 – 6x – 7 (answered by gladley)
1. Simplify the rational expression: Please show work x2 – 6x – 7 x2 – 1... (answered by checkley71)
simplify (5√ 3+7)(-2√ 3-3√... (answered by alicealc)
Multiply: (5√[2] + 3)(√[2] – 2√[3]) (answered by stanbon,MathLover1)
Multiply: (5√[2] + 3)(√[2] – 2√[3]) (answered by Fombitz)
PLEASE PLEASE PLEASE PLEASE PLEASE HELP ME. √(2)[√(4y) - √(18)]... (answered by stanbon)
Simplify... (answered by stanbon)
Rational and Radical Expressions 1. Simplify the rational expression: x2 – 6x – 7 (answered by Edwin McCravy)