How do you factor completely #5x(x + 3) + 6(x + 3)#?

1 Answer
May 17, 2016

Answer:

#(x+3)(5x+6)#

Explanation:

They have already done a lot of the work for you.

The common factor is #(x+3)# so we factor that out giving:

#color(blue)((x+3))color(brown)((5xcolor(green)(+)6))#

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To emphasise how this works:

Consider the example #color(blue)(a)color(brown)((b color(green)(+)c))#

This is saying multiply everything inside the brackets by #a#.

So you have #color(brown)(color(blue)(a xx)b color(green)(+)color(blue)(a xx)c)#

Notice that the #color(green)(+)# is still kept between.

now think of #a" as "(x+3)"#

#color(brown)(color(blue)((x+3)xx)5xcolor(green)(+)color(blue)((x+3)xx)6)#