6. distribute. $3x^{5}(x^{2}-3x + 4)$

Explanation:

Step1: Multiply $3x^5$ by $x^2$

$3x^5\times x^2 = 3x^{5 + 2}=3x^7$

Step2: Multiply $3x^5$ by $-3x$

$3x^5\times(-3x)=-9x^{5+1}=-9x^6$

Step3: Multiply $3x^5$ by $4$

$3x^5\times4 = 12x^5$

Step4: Combine the results

$3x^7-9x^6 + 12x^5$

Answer:

$3x^7-9x^6 + 12x^5$