Sagot :
4x + 7y = 1 ⇒ 12x + 21y = 3
3x + 10y = 15 ⇒ 12x + 40y = 60
-19y = -57
-19 -19
y = 3
4x + 7(3) = 1
4x + 21 = 1
- 21 - 21
4x = -20
4 4
x = -5
(x, y) = (-5, 3)
3x + 10y = 15 ⇒ 12x + 40y = 60
-19y = -57
-19 -19
y = 3
4x + 7(3) = 1
4x + 21 = 1
- 21 - 21
4x = -20
4 4
x = -5
(x, y) = (-5, 3)
4x + 7y = 1
3x + 10y = 15
Multiply the first equation by -3, and the 2nd by 4.
-12x - 21y = -3
12x + 40y = 60
Add the equations:
19y = 57
y = 3
Plug this into any of the two equations to find 'x':
4x + 7y = 1
4x + 7(3) = 1
4x + 21 = 1
Subtract 21 to both sides:
4x = -20
Divide 4 to both sides:
x = -5
So our solution is (-5, 3)
3x + 10y = 15
Multiply the first equation by -3, and the 2nd by 4.
-12x - 21y = -3
12x + 40y = 60
Add the equations:
19y = 57
y = 3
Plug this into any of the two equations to find 'x':
4x + 7y = 1
4x + 7(3) = 1
4x + 21 = 1
Subtract 21 to both sides:
4x = -20
Divide 4 to both sides:
x = -5
So our solution is (-5, 3)