Answer:Final answer is [tex]3x^2-4x+15[/tex]Step-by-step explanation:Given expression is [tex](5x^2+3)-(2x^2+4x-12)[/tex].Now we need to subtract them.We are allowed to subtract like terms only that has same variable with same exponent.[tex](5x^2+3)-(2x^2+4x-12)[/tex][tex]=5x^2+3-2x^2-4x+12[/tex][tex]=5x^2-2x^2-4x+3+12[/tex][tex]=(5-2)x^2-4x+(3+12)[/tex][tex]=(3)x^2-4x+(15)[/tex][tex]=3x^2-4x+15[/tex]Hence final answer is [tex]3x^2-4x+15[/tex]