(12/17)/(48/51) = (12/17)*(51/48) = (12*51)/(17*48) = (12*3*17)/(17*12*4) = 3/4
9- 2 17/20= 8 20/20- 2 17/20= 6 3/20
<span>0,6(x + 1 2/3) = 1,2
x + 1 2/3 = 1,2 : 0,6
x = 2 - 1 2/3
x = 1/3
</span>
Ответ: 130
Пошаговое объяснение:
(3/5)*a + (3/5)*b = 42+36=78
(3/5)(a + b) = 78
a + b = 78/(3/5) = 78*5/3 = 130