[tex]( 2 {x}^{2} + 3x - 1) \times (3x + 5) = 2 {x}^{2} \times 3x + 2 {x}^{2} \times 5 + 3x \times 3x + 3x \times 5 - 1 \times 3x - 1 \times 5 = 6 {x}^{3 } + 10 {x}^{2} + 9 {x}^{2} + 15x - 3x - 5 = 6 {x}^{3} + 19 {x}^{2} + 12x - 5[/tex]
The most important thing is that you can't add x^2 and x for example. You can multiply them and get x^3 but that's it. However, you can add x and x (2x) or x^2 and x^2 (2x^2) or x^3 and x^3 (2x^3) etc.
