12 + (х + 3) = 18 14 - (х - 5) = 9
х + 3 = 18 - 12 х - 5 = 14 - 9
х + 3 = 6 х - 5 = 5
х = 6 - 3 х = 5 + 5
х = 3 х = 10
8 + (4 - х) = 11 15 - (х + 5) = 5
4 - х = 11 - 8 х + 5 = 15 - 5
4 - х = 3 х + 5 = 10
х = 4 - 3 х = 10 - 5
х = 1 х = 5
(х + 4) - 3 = 6
х + 4 = 6 + 3
х + 4 = 9
х = 9 - 4
х = 5
50 = 2*5*5
49 = 7*7
нок = 2*5*5*7*7 = 2450
1. .........................=7,6
1) 4 1/2 - 0,7=4 5/10 - 0,7=4,5-0,7=3,8
2) 1,85+3/20=1,85+15/100=1,85+0,15=2
3) 3,8*2=7,6
2. ....................=7,36
1) 2,6+1 2/5=2,6+1 4/10=2,6+1,4=4
2) 4 - 2 4/25=4 - 2 16/100=4 - 2,16=1,84
3) 4 * 1,84=7,36
3. .........................=6
1) 7 2/5+6,4=7 4/10 +6,4=7,4+6,4=13,8
2) 5,2 - 2 9/10=5,2-2,9=2,3
3) 13,8:2,3=6
4. .......................=9
1) 14 - 2 3/10=14 - 2,3=11,7
2) 3/5 +0,7=6/10+0,7=0,6+0,7=1,3
3) 11,7:1,3=9