Answer:
3x^2-4
Step-by-step explanation:
[tex]\left(5x^2+3x+4\right)-\left(2x^2+1\right)-\left(7x+3\right)\\\\\mathrm{Remove\:parentheses}:\quad \left(a\right)=a\\\\=5x^2+3x+4-\left(2x^2+1\right)-\left(7x+3\right)\\\\-\left(2x^2+1\right)\:\::-2x^2-1\\\\=5x^2+3x+4-2x^2-1-\left(7x+3\right)\\\\-\left(7x+3\right) \:\: : -7x-3\\\\=5x^2+3x+4-2x^2-1-7x-3\\\\Simplify\\\\=3x^2-4x[/tex]
