9. Simplify using the horizontal method. (2n² + 4n+3)(2n - 3) A. 4n³+2n²-6n-9
B. 4n3+6n²-2n-9
C. 4n³-2n²+18n - 9
D. 4n³+14n2-18n- 9


Sagot :

Answer:

A. 4n³+2n²-6n-9

Step-by-step explanation:

➟ (2n²+4n+3)(2n−3)

➟ (2n²+4n+3)(2n+−3)

➟ (2n²)(2n)+(2n²)(−3)+(4n)(2n)+(4n)(−3)+(3)(2n)+(3)(−3)

➟ 4n³−6n²+8n²−12n+6n−9

➟ 4n³+2n²−6n−9