How do you factor completely 14a^2 - 68a + 48?

1 Answer

14a^2-68a+48=2(7a-6)(a-4)

Explanation:

We have:

14a^2-68a+48

We can first factor out the Largest Common Factor of 14, 68, and 48:

  • 14 = 2xx7
  • 68 = 2xx2xx17
  • 48= 2xx2xx2xx2xx3

The Largest Common Factor is 2:

2(7a^2-34a+24)

Now we look for factors in the form of (ax+b)(cx+d) where

  • ac=7
  • bd=24
  • ad+bc=-34

We know the factors for 7=7xx1, so let's set a=7, c=1

The factors for 24=-1xx-24, -2xx-12, -3xx-8, -4xx-6 (because ad+bc is a negative number and we've set ac to be positive, we need these factors to be negative).

Let's try some factors and trial and error our way into this:

acolor(white)(00000)bcolor(white)(0000)c color(white)(00000)dcolor(white)(000000)adcolor(white)(00000)bc color(white)(000)ad+bc

7color(white)(000)-8color(white)(000)1 color(white)(000)-3color(white)(000)-21color(white)(000)-8 color(white)(000)-29

7color(white)(000)-6color(white)(000)1 color(white)(000)-4color(white)(000)-28color(white)(000)-6 color(white)(000)-34

This gives us:

2(7a-6)(a-4)