How do you write #y=3(x-5)(x+2)# in standard form?

1 Answer
Feb 26, 2017

#y=3x^2-9x-30#

Explanation:

#color(blue)((x-5))color(green)((x+2))=#

#{: (underline(xx),underline(" | "),underline(color(blue)x),underline(color(blue)(-5))), (color(green)x," | ",x^2,-5x), (underline(color(green)(+2)),underline(" | "),underline(+2x),underline(-10)), (,color(red)(x^2),color(red)(-3x),color(red)(-10)) :}#

Therefore
#color(white)("XXX")3(x-5)(x+2)=3(color(red)(x^2-3x-10))#

#color(white)("XXXXXXXXXXXX")=3x^2-9x-30#

Note that to be in "standard form" the polynomial must be arranged with the terms in descending degree order (which this already is).