Решим уравнения:
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$$x^2+x+6=-x^2-3x+(-2+2x^2)$$
$$x^2+x+6=-x^2-3x-2+2x^2$$
$$x^2+x+6=-x^2-3x-2+2x^2$$
$$x^2+x+6 - 2x^2 +x^2 +3x +2 = 0$$
$$4x + 8 = 0$$
$$4x = -8$$
$$x = -2$$
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$$-3x^2+5x-3=-x^2+3x+(2-2x^2)$$
$$-3x^2+5x-3=-x^2+3x+2-2x^2$$
$$-3x^2+5x-3 +2x^2 + x^2 -3x -2 = 0$$
$$2x - 5 = 0$$
$$2x = 5$$
$$x = 2.5$$
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$$3x^2-4x+7=x^2-5x+(-1+2x^2)$$
$$3x^2-4x+7=x^2-5x-1+2x^2$$
$$3x^2-4x+7 -2x^2 -x^2 +5x +1 = 0$$
$$x + 8 = 0$$
$$x = -8$$
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$$-4x^2+2x+6=-2x^2+3x-(-3+2x^2)$$
$$-4x^2+2x+6=-2x^2+3x+3-2x^2$$
$$-4x^2+2x+6 + 4x^2 -3x -3 = 0$$
$$-x + 3 = 0$$
$$x = 3$$
Ответ: 1) x = -2; 2) x = 2.5; 3) x = -8; 4) x = 3