How do you multiply $(x+1)(x+4)$ ?

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Answer 1 · 2016-04-18T19:28:13

$x^2+5x+4$

first multiply $x$ with $(x+4)$ and then $1$ with again $(x+4)$
so $x^2+4x+x+4$
$x^2+5x+4$

Answer 2 · 2016-04-18T19:34:43

Use FOIL to help find:

$(x+1)(x+4) = x^2+5x+4$

If you find it helpful, you can use the FOIL mnemonic to help you identify which terms to combine.

$(x+1)(x+4) = overbrace((x*x))^"First" + overbrace((x*4))^"Outside"+overbrace((1*x))^"Inside"+overbrace((1*4))^"Last"$

$=x^2+4x+x+4 = x^2+5x+4$

How do you multiply (x+1)(x+4)(x+1)(x+4)?