How do you FOIL (4z-u)(3z+2u)(4zu)(3z+2u)?

3 Answers
Mar 24, 2018

The FOIL'ed version of the factored expression is 12z^2 +5zu-2u^212z2+5zu2u2

Explanation:

As you may know, FOIL stands for First Outer Inner Last. Using this Mnemonic, we'll work in order.

First:
4zxx3z=4xx3xxzxxz=12z^24z×3z=4×3×z×z=12z2

Outer:
4zxx2u=4xx2xxzxxu=8zu4z×2u=4×2×z×u=8zu

Inner:
-uxx3z=-1xx3xxuxxz=-3uz=-3zuu×3z=1×3×u×z=3uz=3zu

Last:
-uxx2u=-1xx2xxuxxu=-2u^2u×2u=1×2×u×u=2u2

Now, let's put them back together in the expression:

12z^2+8zu-3zu-2u^212z2+8zu3zu2u2

Finally we combine like terms to get our finished expression:

12z^2+(8-3)zu-2u^2=color(red)(12z^2+5zu-2u^2)12z2+(83)zu2u2=12z2+5zu2u2

Mar 24, 2018

12z^2 +5zu -2u^212z2+5zu2u2

Explanation:

The FOIL method:

  1. (4z−u)(3z+2u)(4zu)(3z+2u)
  2. (4z*3z) +(4z * 2u) + (-u*3z) + (-u * 2u)(4z3z)+(4z2u)+(u3z)+(u2u)
  3. 12z^2 +8zu -3zu - 2u^212z2+8zu3zu2u2
  4. 12z^2 +5zu -2u^212z2+5zu2u2

Hope this helps!

Mar 24, 2018

22x^2x2+55uuzz-22u^2u2

Explanation:

FF= First
OO= Outside
II= Inside
LL= Last

(4z-u)(4zu) (3z+2u)(3z+2u)

Since 4z and 3z4zand3z are first you multiply them by each other...

4 * 343 equals 1212
z * zzz equals z^2z2

4z and 2u4zand2u are at the end so you would multiply them together
and get 8uz8uz it can also be 8zu8zu but later on you learn that the letter that comes first in the alphabet is usually at the beginning.

The inside would be
-u and 3zuand3z
In which -u * 3zu3z would equal -3uz3uz

Finally, you solve the last two...
-u * 2uu2u
Which equals -2u^22u2

You're equation should now look like this;
12z^2+8uz-3uz-2u^212z2+8uz3uz2u2

Subtract 8uz and 3uz8uzand3uz - They have common variables
You should get 5uz5uz

Your final equation should look like this;
12z^2+5uz-2u^212z2+5uz2u2