7x²-0.35x=0
0.35x(20x-1)=0
x=0 20x-1⇒x=1/20=0.05
115. 116, 161, 611, 123, 132, 213, 231, 312, 321
118. а) 3/37, 3/73, 7/33, б) 3/3377, 3/3737, 3/3773, 3/7337, 3/7373, 3/7733, 7/3337, 7/3373, 7/3733, 7/7333, 33/377, 33/737, 33/773, 37/337, 37/373,
37/733, 73/337, 73/373, 73/733, 77/333.
119. 1/13, 2/13, 3/13, 4/13, 5/13, 6/13
(- 2a³b)³ * (- 5a²b)² = - 8a⁹b³ * 25a⁴b² = - 200a⁹⁺⁴b³⁺² = - 200a¹³b⁵