Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$10x^2-7x$
Subtract each term to obtain: $(9x^2-3x)-(4x-x^2) \\=9x^2-3x-4x-(-x^2) \\=9x^2-3x-4x+x^2$ Combine like terms to obtain: $=(9x^2+x^2)+(-3x-4x) \\=(9+1)x^2+(-3-4)x \\=10x^2+(-7x) \\=10x^2-7x$