I'm trying to see if I got the problem right x2-2x-99,(x-11)-(x+9)
R randrv New member Joined Feb 27, 2007 Messages 1 Mar 1, 2007 #1 I'm trying to see if I got the problem right x2-2x-99,(x-11)-(x+9)
D Denis Senior Member Joined Feb 17, 2004 Messages 1,707 Mar 1, 2007 #2 randrv said: I'm trying to see if I got the problem right x2-2x-99,(x-11)-(x+9) Click to expand... x^2 - 2x - 99 = (x - 11)(x + 9) So you're correct, except WHY the minus sign? You can check if you're correct by multiplying (x - 11) times (x + 9); x times (x + 9) = x^2 + 9x -11 times (x + 9) = -11x - 99 add 'em together: x^2 + 9x - 11x - 99 = x^2 - 2x - 99 : kapish?
randrv said: I'm trying to see if I got the problem right x2-2x-99,(x-11)-(x+9) Click to expand... x^2 - 2x - 99 = (x - 11)(x + 9) So you're correct, except WHY the minus sign? You can check if you're correct by multiplying (x - 11) times (x + 9); x times (x + 9) = x^2 + 9x -11 times (x + 9) = -11x - 99 add 'em together: x^2 + 9x - 11x - 99 = x^2 - 2x - 99 : kapish?
