Multiplying Two Binomials by a Trinomial

Jason76

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Is this right?

\(\displaystyle (a + b)(c + d)(e + f + g)\)

\(\displaystyle (ae + af + ag)(be + bf + bg)\)

Is this headed in the right direction?
 
Is this right?

\(\displaystyle (a + b)(c + d)(e + f + g)\)

\(\displaystyle (ae + af + ag)(be + bf + bg)\)

Is this headed in the right direction?


\(\displaystyle (a + b)(c + d)(e + f + g)\)

\(\displaystyle = [a* (e + f + g) + b*(e + f + g)](c + d)\)

\(\displaystyle = [ae + af + ag + be + bf + bg](c + d)\)

and continue.....
 
Is this right?

\(\displaystyle (a + b)(c + d)(e + f + g)\)

\(\displaystyle (ae + af + ag)(be + bf + bg)\)

Is this headed in the right direction?
Is what right? You have two expressions on two lines with no indication as to what is supposed to be true of them. If you mean "are they equal?", the most common assumption in such a situation, the answer is no. What is true is that \(\displaystyle (a+ b)(e+ f+ g)= ae+ naf+ ag+ be+ bf+ bg\). That is, the two are added, not multiplied, and "(c+ d)" has nothing to do with it.
 
Is what right? You have two expressions on two lines with no indication as to what is supposed to be true of them. If you mean "are they equal?", the most common assumption in such a situation, the answer is no. What is true is that \(\displaystyle (a+ b)(e+ f+ g)= ae+ naf+ ag+ be+ bf+ bg\). That is, the two are added, not multiplied, and "(c+ d)" has nothing to do with it.

So (c + d) has nothing to do with it. Could you FOIL the the binomials and then multiply them to the trinomial? Multiplying two trinomials or one binomial by a trinomial is understood.
 
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