[tex]a) \ -5x^{2}+4x+6x^{2}-7+x^{2}+5x = 2x^{2}+9x+(-7)\\\\b) \ -2(-2a+3b)-3a(-4+3a-5b) = 4a-6b+12a-9a^{2}+15ab =\\\\=-9a^{2}+15ab+16a + (-6)b\\\\c) \ (-3+x)(-2x+3)-5 = 6x-9-2x^{2}+3x-5 = -2x^{2}+9x+(-14)\\\\d) \ (5-2x)(-2x-3)-3x(3x+1) = -10x-15+4x^{2}+6x-9x^{2}-3x=\\\\=-9x^{2}+(-7)x + (-15)[/tex]
