5×7+7×(-3)=35-21=14
5×(-7)+7×3=-35+21=-14
9×7+9×(-2)=63-18=45 (наибольшее)
9×(-7)+9×2=-63+18=-45
12x = 16 : y - 4
16 : y = 12x + 4
y = 16 : (12x + 4) = 4 : (3x + 1)
y(1) = 4 : (3*1 + 1) = 4 : 4 = 1
Ответ: у = 4 : (3x + 1); у(1) = 1
4 20 4
-- х - --- + --x =36
3 3 3
4x-20+4x
-------------- = 36
3
8x-20=108
8x=128
Х=16