SOLUTION: ok so I'm having trouble on this problem: (-d^2+4d+3)(3d^2-7d+6) im suppose to multiply polynomials but get confused. Im not trying to solve for d or simplify simply multiply. can

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: ok so I'm having trouble on this problem: (-d^2+4d+3)(3d^2-7d+6) im suppose to multiply polynomials but get confused. Im not trying to solve for d or simplify simply multiply. can      Log On


   

Question 730438: ok so I'm having trouble on this problem: (-d^2+4d+3)(3d^2-7d+6)
im suppose to multiply polynomials but get confused. Im not trying to solve for d or simplify simply multiply. can you please show me the vertical and horizontal way? thanks
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
You could use a lattice method. It is essentially the same as either the "horizontal" or the "vertical" way of multiplying. Arrange the terms such that one polynomial forms a row (top) and the other forms a column (along a side). Now you fill in the grid spaces with each partial multiplication. THOSE will be the terms to add and possibly from which to simplify the resulting sum.

Hard to show in this site system but something like this:
_______-d^2__________4d___________3
3d^2
-7d
6

You will have nine grid locations to fill.


_________-d^2__________4d___________3
3d^2_____-3d^4_________12d^3_______9d^2
-7d_____7d^3___________-28d^2______-21d
6_______-6d^2_________24d_________18

This lattice arrangement makes finding which like-terms to combine easy to do. Notice where the d^2 terms are located. Notice where the d^3 terms are located. (Not the ones in the main row and column; the ones in the interior locations.)