) 2 * ( x + 5 ) = 12 2) 84 : ( x - 3 ) = 42
х + 5 = 12 : 2 х - 3 = 84 : 42
х + 5 = 6 х - 3 = 2
х = 6 - 5 х = 2 + 3
х = 1 х = 5
проверка: проверка:
2 * ( 1 + 5 ) = 2 * 6 = 12 84 : ( 5 - 3 ) = 84 : 2 = 42
3) 3 * ( x + 4 ) = 33 4) 45 : ( x - 5 ) = 15
х + 4 = 33 : 3 х - 5 = 45 : 15
х + 4 = 11 х - 5 = 3
х = 11 - 4 х = 3 + 5
х = 7 х = 8
проверка: проверка:
3 * ( 7 + 4 ) = 3 * 11 = 33 45 : ( 8 - 5 ) = 45 : 3 = 15
5) 4 * ( x - 7 ) = 12 6) 6 * ( x - 2 ) = 24
х - 7 = 12 : 4 х - 2 = 24 : 6
х - 7 = 3 х - 2 = 4
х = 3 + 7 х = 4 + 2
х = 10 х = 6
проверка: проверка:
4 * ( 10 - 7 ) = 4 * 3 = 12 6 * ( 6 - 2 ) = 6 * 4 = 24
7) ( x + 3 ) * 3 = 27 8) ( x - 4 ) : 5 = 7
х + 3 = 27 : 3 х - 4 = 7 * 5
х + 3 = 9 х - 4 = 35
х = 9 - 3 х = 35 + 4
х = 6 х = 39
проверка: проверка:
( 6 + 3 ) * 3 = 9 * 3 = 27 ( 39 - 4 ) : 5 = 35 : 5 = 7
9) ( x - 3 ) : 2 = 12 10) ( x - 9 ) * 3 = 12
х - 3 = 12 * 2 х - 9 = 12 : 3
х - 3 = 24 х - 9 = 4
х = 24 + 3 х = 4 + 9
х = 27 х = 13
проверка: проверка:
( 27 - 3 ) : 2 = 24 : 2 = 12 ( 13 - 9 ) * 3 = 4 * 3 = 12
11) ( 3 x + 7 ) * 2 = 32 12) ( 2x - 20 ) : 32 = 6
3х + 7 = 32 : 2 2х - 20 = 6 * 32
3х + 7 = 16 2х - 20 = 192
3х = 16 - 7 2х = 192 + 20
3х = 9 2х = 212
х = 9 : 3 х = 212 : 2
х = 3 х = 106
проверка: проверка:
( 3 * 3 + 7 ) * 2 = 16 * 2 = 32 (2 * 106-20) :32 = 192:32 = 6
13) ( 42 + 2x ) : 2 = 32 14) ( 5x - 7 ) * 5 = 15
42 + 2х = 32 * 2 5х - 7 = 15 : 5
42 + 2х = 64 5х - 7 = 3
2х = 64 - 42 5х = 3 + 7
2х = 22 5х = 10
х = 22 : 2 х = 10 : 5
х = 11 х = 2
проверка: проверка:
( 42 + 2 * 11 ) : 2 = 64 : 2 = 32 ( 5 * 2 - 7 ) * 5 = 3 * 5 = 15
15) ( 13 - 2x ) * 3 = 27 16) ( 40 - 4x ) : 2 = 16
13 - 2х = 27 : 3 40 - 4х = 16 * 2
13 - 2х = 9 40 - 4х = 32
2х = 13 - 9 4х = 40 - 32
2х = 4 4х = 8
х = 4 : 2 х = 8 : 4
х = 2 х = 2
проверка: проверка:
( 13 - 2 * 2 ) * 3 = 9 * 3 = 27 ( 40 - 4 * 2 ) : 2 = 16
17) ( 63 - 9x ) : 3 = 15 18) 4 * ( x - 3 ) = 12
63 - 9х = 15 * 3 х - 3 = 12 : 4
63 - 9х = 45 х - 3 = 3
9х = 63 - 45 х = 3 + 3
9х = 18 х = 6
х = 18 : 9
х = 2
проверка: проверка:
( 63 - 9 * 2 ) : 3 = 45 : 3 = 15 4 * ( 6 - 3 ) = 4 * 3 = 12
19) 5 * ( x + 5 ) = 45 20) 3 * ( x - 7 ) = 9
х + 5 = 45 : 5 х - 7 = 9 : 3
х + 5 = 9 х - 7 = 3
х = 9 - 5 х = 3 + 7
х = 4 х = 10
проверка: проверка:
5 * ( 4 + 5 ) = 5 * 9 = 45 3 * ( 10 - 7 ) = 3 * 3 = 9
Пошаговое объяснение:
насдоровья
7.
2,25•(9 11/18-7,5)-8 1/3:3 1/3=2,25
1)9 11/18-7 5/10=9 55/90-7 45/90=
2 1/9
2)2,25•2 1/9=225/100•19/9=475/100
4,75
3)8 1/3:3 1/3=25/3:10/3=5/2=2,5
4)4,75-2,5=2,25
8.
81/88•(6-1 13/15•1 19/21)=2,25
1)1 13/15•1 19/21=28/15•40/21=32/9
=3 5/9
2)6-3 5/9=5 9/9-3 5/9=2 4/9
3)81/88•2 4/9=81/88•22/9=9/4
=2,25
9.
(5 1/16-1 1/8)(5/6+3/14)=4,125
1)5 1/16-1 1/8=5 1/16-1 2/16=3 15/16
2)5/6+3/14=35/42+9/42=44/42=
1 1/21
3)3 15/16•1 1/21=63/16•22/21=33/8=
4 1/8=4,125
10.
5 1/16-1 1/8•(5/6+3/14)=3 99/112
1)5/6+3/14=35/42+9/42=44/42=1 1/21
2)1 1/8•1 1/21=9/8•22/21=33/28=
1 5/28
3)5 1/16-1 5/28=5 7/112-1 20/112=
3 99/112
11.
4/5+4/493•(7 11/12+5 7/9)=41/45
1)7 11/12+5 7/9=7 33/36+5 28/36=
12 61/36=13 25/36
2)4/493•13 25/36=4/493•493/36=
1/9
3)4/5+1/9=36/45+5/45=41/45
12.
(4/5+4/7)•(3 3/8+2 11/14)=12 138/245
1)4/5+4/7=28/35+20/35=48/35=
1 13/35
2)3 3/8+2 11/14=3 21/56+2 44/56=
5 65/56=6 9/56
3)1 13/35•6 9/56=48/35•513/56=
3078/245=12 138/245
13.
(8-2 1/7•3 1/9)•27/44=9/11
1)2 1/7•3 1/9=15/7•28/9=20/3=6 2/3
2)8-6 2/3=7 3/3-6 2/3=1 1/3
3)1 1/3•27/44=4/3•27/44=9/11
14.
(2 13/48+2 5/12):3 3/4-9 3/4:12=7/16
1)2 13/48+2 5/12=2 13/48+2 20/48=
4 33/48=4 11/16
2)4 11/16:3 3/4=75/16:15/4=5/4=1 1/4
3)9 3/4:12=39/4:12/1=39/48
4)1 1/4-39/48=1 12/48-39/48=21/48
=7/16
15.
(4 3/4-2):33/2+1 6/11:17/8=59/66
1)4 3/4-2=2 3/4
2) 2 3/4: 33/2=11/4:33/2=1/6
3)1 6/11:17/8=17/11:17/8=8/11
4)1/6+8/11=11/66+48/66=59/66
Пошаговое объяснение:
1) х + (-5) = 2;
Х=2+5
Х=7
7+(-5)=2
2=2
4) - 6 + х = -2;
Х=-2+6
Х=4
-6+4=-2
-2=-2
2) 8 + y = -3;
У=-3-8
У=-11
8+(-11)=-3
-3=-3
5) y + 7 = -13;
У=-13-7
У=-20
-20+7=-13
-13=-13
3) 14 + х = -6;
Х=-6-14
Х=-20
14+(-20)=-6
-6=-6
6) x + 11 = -4.
Х=-4-11
Х=-15
15+11=-4
-4=-4