Б) 3/8у+у-1/4у =3
(при у=2 2/3 и 4/9)
3/8×2 2/3+2 2/3- 1/4×2 2/3=3
1. 3/8×2 2/3=3/8×8/3=3×8:8×3=1
2. 1/4×8/3=1×8:4×3=2/3
3. 1+2 2/3 -2/3=3
3/8×4/9+4/9-1/4×4/9=1/2
1. 3/8×4/9=3×4:8×9=1/6
2. 1/4×4/9=1×4:4×9=1/9
3. 1/6+4/9-1/9=6/36+16/36-4/36=18/36=1/2
г) 1/3х+3/4х-4/9х=
( при х= 1 13/23 и х=4/46)
1/3×1 13/23+3/4×1 13/23-4/9×1 13/23=1
1. 1/3×1 13/23=1/3×36/23=1×36:3×23=12/23
2. 3/4×36/23=3×36:4×23=27/23
3. 4/9×36/23=4×36:9×23=16/23
4. 12/23+27/23-16/23=23/23=1
1/3×4/46+3/4×4/46-4/9×4/46=1/18
1. 1/3×4/46=1×4:3×46=4/138
2. 3/4×4/46=3×4:4×46=3/46
3. 4/9×4/46=4×4:9×46=16/414
4. 4/138+3/46-16/414=4/138+9/138-16/414=
=13/138-16/414=39/414-16/414=23/414=1/18