How do you multiply 3y ^ { 2} + 6y + 5 and y - 9 using the vertical format?

1 Answer
Mar 15, 2017

3y^3-21y^2-49y -45

Explanation:

Multiplying in vertical format is the same as long multiplication with numbers:

" "3y^2 +6y+5
ul(xx" "color(blue)(y)color(red)( -9)" "larr muliply each term by the top row
color(blue)(3y^3+6y^2+5y
ul(" "color(red)(-27y^2-54y-45))" "larr like terms under each other
ul(3y^3-21y^2-49y -45)" "larradd like terms