А) х=12; у=17
Б) х=-7; у=-10
С) у=12; х=11
Д) х=2 ; у= 13
Е) x=3/2; y=-1/2
Пошаговое объяснение:
А) 2*(х-5)=у-3
х+5=у
2(х-5)=х+5-3; 12+5=у
х=12
у=17
ответ : х=12; у=17
Б) 3*(х – у) = 9
2*х = у – 4
3(x-y)=9
y=4+2x
3(x-(4+2x))=9; y=4+2(-7)
x=-7
y=-10
ответ: х=-7; у=-10
С) 3*(у – 6) – 2*(4 – х ) = 12
4Х + 2у + 4 = 11
3(y-6)-8+6x=12
y=7/2-2x
3(7/2-2x-6) - 2(4-x)=12
x=-55/8
y=7/2-2(-55/8)
y=69/4
ответ: у=12; х=11
Д) х + у – 10 = 5
у – х = 11
x+y=15
-x+y=11
2y=26 ; -x+13=11
y=13
x=2
ответ: х=2 ; у= 13
Е) 3х – 5 = у
Х + 2 = у
3x-y=5
x-y=2
2x=3
ответ : x=3/2; y=-1/2
540.
1) 9/10 * 20/27 + 5/16 : 10/24 - 5/9 * 1 7/20 = 2/3
1) 9/10 * 20/27 = 1/1 * 2/3 = 2/3
2) 5/16 : 10/24 = 5/16 * 24/10 = 1/4 * 6/2 = 1/2 * 3/2 = 3/4
3) 5/9 * 1 7/20 = 5/9 * 27/20 = 1/1 * 3/4 = 3/4
4) 2/3 + 3/4 - 3/4 = 2/3
2) 69/70 * 7/23 - 4/25 : 4/5 + 3/5 * 25/36 = 1/2
1) 69/70 * 7/23 = 3/10 * 1/1 = 3/10
2) 4/25 : 4/5 = 4/25 * 5/4 = 1/5
3) 3/5 * 25/36 = 1/1 * 5/12 = 5/12
4) 3/10 - 1/5 + 5/12 = 18/60 - 12/60 + 24/60 = 30/60 = 1/2 = 0,5
3) 120/169 * 13/60 + 200/243 : 100/81 - 1/13 * 10 = - 2/39
1) 120/169 * 13/60 = 2/13 * 1/1 = 2/13
2) 200/243 : 100/81 = 200/243 * 81/100 = 2/3
3) 1/13 * 10/1 = 10/13
4) 2/13 + 2/3 - 10/13 = 3/39 + 25/39 - 30/39 = -2/39
4) 125/147 * 21/50 - 70/119 * 17/210 - 3/14 * 7/9 = 1/7
1) 125/147 * 21/50 = 5/7 * 1/2 = 5/14
2) 70/119 * 17/210 = 1/7 * 1/3 = 1/21
3) 3/14 * 7/9 = 1/2 * 1/3 = 1/6
4) 5/14 - 1/21 - 1/6 = 15/42 - 2/42 - 7/42 = 6/42 = 1/7
541.
1) 1 2/9 : 3 2/3 + 4 2/5 : (7/10 + 2 3/5) - (3/17 - 1 16/17 : 11) = 1 2/3
1) 1 2/9 : 3 2/3 = 11/9 : 11/3 = 11/9 * 3/11 = 1/3
2) 7/10 + 2 3/5 = 7/10 + 2 6/10 = 2 13/10 = 3 3/10
3) 4 2/5 : 3 3/10 = 22/5 : 33/10 = 22/5 * 10/33 = 2/1 * 2/3 = 4/3 = 1 1/3
4) 1 16/17 : 11 = 33/17 * 1/11 = 3/17
5) 3/17 - 3/17 = 0
6) 1/3 + 1 1/3 - 0 = 1 2/3
2) 5/6 + 2 3/4 : 4 8/9 * 2 2/3 - 1 2/3 + (5/38 * 1 1/3 - 10/57 = 2/3
1) 2 3/4 : 4 8/9 = 11/4 : 44/9 = 11/4 * 9/44 = 1/4 * 9/4 = 9/16
2) 9/16 * 2 2/3 = 9/16 * 8/3 = 3/2 = 1 1/2
3) 5/38 * 1 1/3 = 5/38 * 4/3 = 5/19 * 2/3 = 10/57
4) 10/57 - 10/57 = 0
5) 5/6 + 1 1/2 - 1 2/3 = 5/6 + 1 3/6 - 1 4/6 = 4/6 = 2/3
2) 533,187-78=455,187
3) 619,903+47=666,903
4) 26,888+4,74=31,628
5) 723-177,302=545,698
6) 7,5+234,812=243,312
7) 472,3-50,733=421,567
8) 911,277-28,66=882,617