# 3.2 + – expressions

To add the expressions you add the like terms firstly. For example, to add $6m+9p$ and $3d+2p$, we have to add $6m+9p+2p+3d$. As the only like terms are the p’s, we add these together, so we have $6m+\boldsymbol{9p}+\boldsymbol{2p}+3d=6m+\boldsymbol{11p}+3d$

“What’s the difference between a trinomial, and the binomial?” Demi asked.

“Binomials means ‘bi’ that means two, binomial is a polynomial with two terms,” Jamie explained, “you see thats why they added ‘bi’ into the word binomial and notice that binomial and polynomial both have ‘nomial’ in their word.”

“You can remember this because a bicycle has 2 wheels,” Demi said, “but what about trinomial?”

“Trinomial is the same as binomial however it has three terms,” Jamie said, ” ‘tri’ means three so it does have three terms.”

“You can remember this because a tricycle has 3 wheels” Demi replied.

For example, to add the trinomials $9e+7f+3h$ and $10e+5f+h$ (remembering that $h=1h$), this will give us $9e+7f+3h+10e+5f+1h=19e+12f+4h$, grouping together the e’s, the f’s and the h’s.

# Subtracting Binomial

To subtract the expressions you simply subtract the like terms firstly. For example, subtract $4w-2$ from $6w-20$, will get $6w-20-4w-2=2w-18$.

# Subtracting Trinomial

Example of subtracting algebra trinomial. For example, subtracting $4q-r-5u$ (remembering $r=1r$), will get $8q-2r-9u-4q-1r-5u=4q-r-4u$.