# How do you FOIL  (1 - 3y) (7 - 4y)?

May 24, 2015

FOIL is short for First, Outside, Inside, Last
It helps you to remember all the combinations when multiplying two bracketed terms each containing two expressions.

'First' : $\left(1 \cdot 7\right) = 7$
'Outside': $\left(1 \cdot - 4 y\right) = - 4 y$
'Inside': $\left(- 3 y \cdot 7\right) = - 21 y$
'Last': $\left(- 3 y \cdot - 4 y\right) = 12 {y}^{2}$

$\left(1 - 3 y\right) \left(7 - 4 y\right)$
($= F + O + I + L$ )
$= 7 - 4 y - 21 y + 12 {y}^{2}$
$= 7 - 25 y + 12 {y}^{2}$