Hey everyone, what are the common equations to factor that should be memorized...like (a+b)^2 = a^2 + b^2 + 2ab I know every once in a while some people post the list in random posts but I can't find them...thank you! Jason

JGaynor wrote:Hey everyone, what are the common equations to factor that should be memorized...like (x-y)^2 = (x+y)(x-y) I know every once in a while some people post the list in random posts but I can't find them...thank you! Jason (x-y)^2 # (x-y)(x+y) its = (x-y)(x-y)=x^2-2x+y^2 (a-b)^2;(a-b)^3;(a^3-b^3);a^2-b^2

(a+b)^2 = a^2 + b^2 + 2ab (a-b)^2 = a^2 + b^2 -2ab a^2 - b^2 = (a-b)(a+b) (a + b)^3 = a^3 + 3a^2b + 3ab^2 + b^3 (a - b)^3 = a^3 - 3a^2b + 3ab^2 - b^3 a^3 - b^3 = (a-b)(a + ab + b^2) HTH

JGaynor wrote:Hey everyone, what are the common equations to factor that should be memorized...like (x-y)^2 = (x+y)(x-y) I know every once in a while some people post the list in random posts but I can't find them...thank you! Jason Your above formula is stated wrong. The L.H.S is x^2 - y^2. Do edit it

Thank you! Keep them coming if there any more....this helps a lot!

How about a way to factor ax^2 + bx + c = 0 if the roots (solutions) are rational numbers? Write (ax + p)(ax + q)/a where pq = ac and p+q = b For example 6x^2 + x - 40 pq =240 p + q = -1 p= 15 q= -16 (6x + 15)(6x - 16)/6 =3(2x+5)(3x - 8)2 / 6 (2x+5)(3x - 8) Another example: 24x^2 - 5x - 36 pq= 24(-36)= - (2^5)(3^3) p+q = - 5 p= -2^5=-32 q=3^3= 27 (24x -32)(24x +27)/24

Really the property of quadratic equation i.e. for a quad. eq. ax^2 + bx + c = 0 sum of roots = -b/a and product of roots = c/a is very helpful and we can solve the problem very easily..