пожалуйста помогите решить уравнения методом подстановки.
1) у=-3х
5х+3у=12
2) х-2у=5
2х+3у=-4
3) 2х+3у=16
3х-2у=11
пожалуйстаааааа
1) у=-3х
5х+3у=12
2) х-2у=5
2х+3у=-4
3) 2х+3у=16
3х-2у=11
пожалуйстаааааа
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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!5x + 3y = 12
y = -3
5x + 3*(-3x) = 12
5x - 9x = 12
-4x = 12
x = -3
x = -3
y = -3*3
x = -3
y = -9
2) x - 2y = 5
2x + 3y = -4
x = 5 + 2y
2(5 + 2y) + 3y = -4
10 + 4y + 3y = -4
7y = -4-10
7y = -14
y = -2
y = -2
x = 5 + 2*(-2)
y = -2
x = 1
3) 2x + 3y = 16
3x - 2y = 11
2x = 16 - 3y
3x - 2y = 11
x =(16 - 3y)/2
3* (16 - 3y)/2 - 2y = 11
(48 - 9y)/2 - 2y = 11
24 - 4,5y - 2y = 11
-6,5y = 11 - 24
- 6,5y = -13
y = -13 : (-6,5)
y = 2
x = (16 - 3*2)/2
x = 10/2
x = 5
x = 5
y = 2