## Algebra 1: Common Core (15th Edition)

12 is co-efficient of $x^{2}$
4x(5$x^{2}$+3x+7) (4x$\times$5$x^{2}$)+(4x$\times$3x)+(4x$\times$7) 20$x^{3}$+12$x^{2}$+28x The co-efficient of $x^{2}$ is the number that goes with it which is 12.