Решитее...... Пж....
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1..S*(7-5r)-r*(8-5s)/rs 7s-5rs-8r+5rs/rs 7s-8r/rs 2..4t*(9-5z)+5z*(5+4t)/20tz 36t-20tz+25z+20tz/20tz 36t-25z/20tz