<span>610-200+10 = 610-200 = 410+10 = 420
620-200+20 = 620-200 = 420 + 20 = 440
630-200+30 = 630-200 = 430+30 = 460
44:11x17 = 44</span>:11 = 4x17 = 68<span>
80:16x9 = 80</span>:16 = 5x<span>9 = 45
72:8x11 = </span>72:8 = 11<span>x</span>9 = 99
Від 2 до 9 будь-яке з цих чисел
X^2-3x-2x+6-x^2=x^2+4x+2x+8+x^2-(x^2-2x+1)
-5x+6=2x^2+6x+8-x^2+2x-1
-5x+6=x^2+8x+7
x^2+13x+1=0
D=169-4=165
x1=(-13+sqrt(165))/2
x2=(-13-sqrt(165))/2