How do you evaluate #(- 4r ^ { 2} - r + 2) ( 4r ^ { 2} - 5r + 4)#?

1 Answer
Jim G.
Dec 8, 2017

#-16r^4+16r^3-3r^2-14r+8#

Explanation:

#"each term in the second factor is multiplied by each"#
#"term in the first factor"#

#rArr(color(red)(-4r^2-r+2))(4r^2-5r+4)#

#=color(red)(-4r^2)(4r^2-5r+4)color(red)(-r)(4r^2-5r+4)#
#color(white)(xxxx)color(red)(+2)(4r^2-5r+4)#

#=-16r^4+20r^3-16r^2-4r^3+5r^2-4r+8r^2-10r+8#

#=-16r^4+16r^3-3r^2-14r+8larrcolor(blue)"in standard form"#

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