Question 339673
1) Solve by factoring and using the principle of zero products.
x2 + 9x = 0
Hint:  both terms have a factor of x
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2) Factor completely.
x2 - 50xy + 625y2
Hint:  the 1st and last terms are squares.
3) Factor completely.
3x3 + 24x2 + 48x
Factor out a 3x.  Then the 1st and last terms are squares.
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4) Factor completely.
x4 - 24x2 - 25
It will be (x^2 + a)*(x^2 + b)
ab = -25, so the signs are different.
a+b = -24