Answer:
Step-by-step explanation:
If the roots are 7 and 3, then x = 7 and x = 3 are solutions. In factor form, x = 7 is (x - 7); in factor form, x = 3 is (x - 3). We FOIL these together to get
[tex]x^2-3x-7x+21[/tex] which simplifies to
[tex]x^2-10x+21[/tex] and we distribute in the 4:
[tex]4(x^2-10x+21)[/tex] to get
[tex]4x^2-40x+84[/tex] which is another way to write the last choice you're given.