Odpowiedź :
[tex]x^2+2x+3+4x^2+5x+6=7+6x+5x^2\\5x^2+7x+9=7+6x+5x^2\\7x-6x=7-9\\x=-2\\\\\\\\2x^3-3x^2+4x+7=9+5x^3-4x^2-3x^3+x^2\\4x+7=9\\4x=2\\x=\frac{1}{2}[/tex]
a)
[tex]x^{2} + 2x + 3 + 4x^{2} + 5x + 6 = 7 + 6x + 5x^{2} \\x^{2} + 2x + 4x^{2} + 5x - 6x - 5x^{2} = 7 -3 - 6\\x = - 2[/tex]
b)
[tex]2x^{3} - 3x^{2} + 4x + 7 = 9 + 5x^{3} - 4x^{2} - 3x^{3} + x^{2} \\2x^{3} - 3x^{2} + 4x - 5x^{3} + 4x^{2} + 3x^{3} - x^{2} = 9 - 7\\4x = 2[/tex]
[tex]x=\frac{1}{2}[/tex]