Answer:
(2.8×10¹)x⁶y⁴
Explanation:
Multiplication can be done in the usual way, then the number converted to scientific notation. Scientific notation does not apply to the variables.
![(7x^3y^2)(4x^3y^2)=(7\cdot 4)x^(3+3)y^(2+2)=28x^6y^4\\\\=2.8\cdot 10^1x^6y^4](https://img.qammunity.org/2019/formulas/mathematics/college/x06j3gow2gv1jo2dh0alxb6o5rr62agcd7.png)
_____
If you write the numbers in scientific notation to start, then do the multiplication, the effect is virtually the same: an adjustment is needed in the product to get it back to scientific notation.
(7)(4) = (7×10⁰)(4×10⁰) = 7·4×10⁰⁺⁰ = 28×10⁰ = 2.8×10¹