Question

Multiply (in vertical and horizontal arrangement):

(3) (3x² + 7x) × 2x

Answer 1

(3) (3x² + 7x) × 2x
Vertical arrangement:
$\begin{array}{c}\begin{array}{cccc}& 3x^2& +& 7x\end{array}\\ \begin{array}{cccc}\times & & & 2x\end{array}\\ \overline{\underline{\begin{array}{cccc}& 6x^3& +& 14x^2\end{array}}}\end{array}$
Horizontal arrangement:
(3x² + 7x) × 2x
= (2x × 3x²) + (2x × 7x)
= (2 × x × 3 × x × x) + (2 × x × 7 × x)
= ((2 × 3) × (x × x × x)) + ((2 × 7) × (x × x))
= 6x³ + 14x²