Ответы
Объяснение:
1.
{у=9х+5
{у=23х-6
23х-6=9х+5
23х-9х=5+6
14х=11
х=11/14
у=9•11/14+5
у=99/14+5
у=169/14
(11/14;169/14)
2.
{у=13х-7
{у=5х+24
13х-7=5х+24
13х-5х=24+7
8х=31
х=31/8
у=5•31/8+24
у=155/8+24
у=347/8
(31/8;347/8)
3.
{у= -8х-15
{у= -21х+11
-8х-15= -21х+11
-8х+21х=11+15
13х=26
х=2
у= -8•2-15
у= -16-15
у= -31
(2; -31)
4.
{5х-3у=14
{2х+у=10 у=10-2х
5х-3(10-2х)=14
5х-30+6х=14
11х=14+30
11х=44
х=44:11
х=4
у=10-2•4
у=10-8
у=2
(4;2)
5.
{х+5у=35 х=35-5у
{3х+2у=27
3(35-5у)+2у=27
105-15у+2у=27
-13у=27-105
-13у= -78
у= -78:(-13)
у=6
х=35-5•6
х=35-30
х=5
(5;6)
6.
{7х-2у=15
{2х+у=9 у=9-2х
7х-2(9-2х)=15
7х-18+4х=15
11х=15+18
11х=33
х=33:11
х=3
у=9-2•3
у=9-6
у=3
(3;3)
7.
{2х-у=2 у=2х-2
{3х-2у=3
3х-2(2х-2)=3
3х-4х+4=3
-х=3-4
-х= -1
х=1
у=2•1-2
у=2-2
у=0
(1;0)
8.
{5у-х=6 х=5у-6
{3х-4у=4
3(5у-6)-4у=4
15у-18-4у=4
11у=4+18
11у=22
у=22:11
у=2
х=5•2-6
х=10-6
х=4
(4;2)
9.
{3х+4у=55
{7х-у=56 у=7х-56
3х+4(7х-56)=55
3х+28х-224=55
31х=55+224
31х=279
х=279:31
х=9
у=7•9-56
у=63-56
у=7
(9;7)
10.
{у= -11х+9
{у= -21х+11
-11х+9= -21х+11
-11х+21х=11-9
10х=2
х=2:10
х=0,2
у= -11•0,2+9
у= -2,2+9
у=6,8
(0,2;6,8)
11.
{х+3у=2 х=2-3у
{2х+3у=7
2(2-3у)+3у=7
4-6у+3у=7
-3у=7-4
-3у=3
у=3:(-3)
у= -1
х=2-3•(-1)
х=2+3
х=5
(5;-1)
12.
{4у-х=11 х=4у-11
{6у-2х=13
6у-2(4у-11)=13
6у-8у+22=13
-2у=13-22
-2у= -9
у=4,5
х=4•4,5 -11
х=18-11
х=7
(7;4,5)
13.
{х-2у=3 х=3+2
{5х+у=4
5(3+2у)+у=4
15+10у+у=4
11у=4-15
11у= -11
у= -11:11
у= -1
х=3+2•(-1)
х=3-2
х=1
(1;-1)
14.
{3у+8х=5
{у+4х=2 у=2-4х
3(2-4х)+8х=5
6-12х+8х=5
-4х=5-6
-4х= -1
х= -1:(-4)
х=0,25
у=2-4•0,25
у=2-1
у=1
(0,25;1)
15
{5х+у=3 у=3-5х
{3х-2у=7
3х-2(3-5х)=7
3х-6+10х=7
13х=7+6
13х=13
х=13:13
х=1
у=3-5х
у=3-5•1
у=3-5
у= -2
(1;-2)