How do you find the quotient of #(x^2+x-20)div(x-4)#?

3 Answers
Jun 12, 2017

#x+5#

Explanation:

#color(white)(wwwww)x+5#
#x-4 )bar(x^2+x-20)#
#color(white)(www)ul(color(red)(-)x^2color(red)(+)4x)" "larr# subtract
#color(white)(wwwwwwww)5x-20#
#color(white)(wwn.....ww)color(red)(-)ul(5xcolor(red)(+)20)#
#color(white)(wwwwwwwwwwwwww)0" "# remainder

#(x^2 +x-20) div (x-4) = x+5#

Jun 12, 2017

#x+5#

Explanation:

#"factorise the numerator and simplify"#

#rArr(x^2+x-20)/(x-4)#

#=((x+5)cancel((x-4)))/cancel((x-4))#

#=x+5larrcolor(red)" quotient"#

Jun 12, 2017

Factorise and cancel like factors.

#x+5#

Explanation:

In a division such as #48 div 6#, we could find the quotient by finding factors:

#48/6 = (8 xx 6)/6" "larr# like factors can cancel #" "6/6 =1#

#(8 xx cancel6)/cancel6 = 8#

In the same way we can find the quotient by factorising the numerator:

#(x^2 +x -20)/((x-4)) = ((x+5)(x-4))/((x-4))#

Cancel the like factors:

# ((x+5)cancel((x-4)))/cancel((x-4))#

# = x+5#