Answer:
All are incorrect
Step-by-step explanation:
Required
Determine which is correct or not
[tex](a)\ 2x * 2x = 4x[/tex]
This is incorrect because:
[tex]2x * 2x = 2 * 2 * x*x[/tex]
[tex]2x * 2x = 4x^2[/tex] ---- fixed
[tex](b)\ 3x^3 * 3x^3 = 9x^9[/tex]
This is incorrect because:
[tex]3x^3 * 3x^3 = 3 * 3 * x^3 * x^3[/tex]
[tex]3x^3 * 3x^3 = 9x^(3+3)[/tex]
[tex]3x^3 * 3x^3 = 9x^6[/tex] ---- fixed
[tex](c)\ 4x(4x + 5) =8x + 5[/tex]
This is incorrect because:
[tex]4x(4x + 5) =4x * 4x + 4x * 5[/tex]
[tex]4x(4x + 5) =16x^2 + 20x[/tex] ---- fixed