4.
a) -x = 2.7; x = -2.7
б) -6 + x = 0; x = 6;
в) 5 - а = 12; -а = 7; a = -7;
г) n - 1 3/5 = 4,5; n = 8/5 - 45/10; n = 16/10 - 45/10; x = -29/10= - 2.9
д) 0.12 + x = - 0.08; x = -0.12 - 0.08; x = - 0.2;
е) x -(-0.6) = 1.6; x+0.6=1.6; x = 1.6 - 0.6; x =1
ж) |x-3| = 1; x = 2 и 4
з) |x+1| = 3; x = 2 и -4
5.
a) 1.8 + 2.5 = 4.3
б) 5/6 = 10/12; 10/12-7/12 = 3/12 или 1/4
6.
после первого повышения 600 * 1,05 = 630
после второго 630 * 1,1 = 693