You can
put this solution on YOUR website!
Solve: 2x(x+3)= x + 25
Distribute the 2x:
2x² + 6x = x + 25
Get 0 on the right and the left side in descending
order of powers of x:
2x² + 5x - 25 = 0
Multiply the 2 by the 25, getting 50.
Think of two positive integers, which have DIFFERENCE*** 5.
These are 10 and 5. So use 10 and 5 to rewrite the
middle term 5x as 10x - 5x.
2x² + 10x - 5x - 25 = 0
Factor the first two terms 2x² + 10x as 2x(x+5)
Factor the last two terms -5x-25 as -5(x+5)
2x(x+5) - 5(x+5) = 0
Factor out the parentheses (x+5) which leaves the 2x in the
first term and -5 in the second to put in another set of parentheses:
(x+5)(2x - 5) = 0
Set each factor = 0
x+5=0 gives solution x=-5
2x-5=0 gives solution x=
-------------------------------------------------------
***Footnote: This is DIFFERENCE because the last sign is
MINUS. When the last sign is PLUS, this would be SUM.
Edwin
