1)14к=600-180
14к=420
к=30
2)8y·5=280
8y=280÷5
8y=56
y=7
3)146а-97=63+182
146а-97=245
146а=245+97
146а=342
а=2,34
4 : 4 4/5 + 2 2/7 * 5 1/4 - 7 11/12 = 4 11/12
1) 4 : 4 4/5 = 4 : 24/5 = 4 * 5/24 = 20/24 = 5/6
2) 2 2/7 * 5 1/4 = 16/7 * 21/4 = (4*3)/(1*1) = 12
3) 5/6 + 12 = 12 5/6
4) 12 5/6 - 7 11/12 = 12 10/12 - 7 11/12 = 11 22/12 - 7 11/12 = 4 11/12
Пояснения:
4 4/5 = (4*5+4)/5 = 24/5
2 2/7 = (2*7+2)/7 = 16/7
5 1/4 = (5*4+1)/4 = 21/4
5/6 = (5*2)/(6*2) = 10/12 - доп.множ. 2
8=2x-3
2x-3-8=0
2x-11=0
2x=11
x=11/2
x=5,5