(-2x^8)x3y^9x2x^4

3x^12y^9
-12x^72y^9
-12xy^21
-12x^12y^9

-12x^12y^9

To simplify the expression (-2x^8)(3y^9)(2x^4), you can use the properties of exponents and follow these steps:

Step 1: Multiply the coefficients (-2) and (3) to get -6.
-6x^8y^9x^4

Step 2: Combine the x-terms by adding the exponents.
-6x^(8+4)y^9

Step 3: The final expression is -6x^12y^9.

So, the simplified expression is -6x^12y^9.

To simplify the expression (-2x^8) × 3y^9 × 2 × x^4, follow these steps:

Step 1: Multiply the numerical coefficients (-2) and (3) together.
-2 × 3 = -6

Step 2: Multiply the x-terms together.
x^8 × x^4 = x^(8+4) = x^12

Step 3: Multiply the y-terms together.
y^9 remains as it is since there is no other y-term to multiply.

Step 4: Multiply the numerical coefficient (-6) with the simplified x^12 and y^9 terms.
-6 × x^12 × y^9 = -6x^12y^9

Therefore, the expression (-2x^8) × 3y^9 × 2 × x^4 simplifies to -6x^12y^9.