N°92.
1) 14/35 -(7x)/35=55/35 |×35
14-7x=55; 7x=14-55; x=-41/7; x=-5 6/7
2)(3x)/5=6/3 +x/3; 9x=5(6+x); 9x-5x=30; x=30/4; x=15/2; x=7,5
3) x/3 +x/5=8; 5x+3x=8·15; 15x=8·15; x=8
4) y/3 +y/4=14; 4y+3y=14·12; 7y=14·12; y=2·12; y=24
N°94.
1) 0,71x+1,98=0,37x-1,76 |×100
71x-37x=-176-198; x=-374/34; x=-11
2) 0,18y-7,4=0,05y-5,71 |×100
18y-5y=740-571; y=169/13; y=13
3) 5(5x-1)-2,7x+0,2x=6,5-0,5x |×10
250x-50-25x=65-5x |5
45x-10=13-x; 45x+x=13+10; x=23/46; x=1/2; x=0,5
4) 0,36x-0,6=0,3(0,4x-1,2) |×100/6
6x-10=5(0,4x-1,2)
6x-10=2x-6 |2
3x-x=5-3; x=2/2; x=1