## Algebra: A Combined Approach (4th Edition)

(a) = 6x +12 (b) $=9{x^2} + 36x + 35$
a) (3x + 5) + (3x + 7) $\Longrightarrow$ This is addition of the two polynomials. = 3x + 3x + 5 + 7 =6x +12 b) (3x + 5)(3x+7) $\Longrightarrow$ This was multiplication of two polynomials. =3x(3x) + 3x(7) + 3x(5) + 5(7) $=9{x^2} + 21 x + 15x + 35$ $=9{x^2} + 36x + 35$ The difference between operations in (a) and (b) is that: (a) has the plus/add (+) sign. This means that you have to combine all like/similar terms. (b) is multiplication. Observe that there is no sign in between. This shows that the two polynomials have to be multiplied. Similar terms and non-similar terms are all multiplied.