sofia4696
sofia4696 sofia4696
  • 12-02-2021
  • Mathematics
contestada

Solve the system by substitution.
3x + y = 20
-7y=x

Please help

Respuesta :

sqdancefan
sqdancefan sqdancefan
  • 13-02-2021

9514 1404 393

Answer:

  (x, y) = (7, -1)

Step-by-step explanation:

The expression for x makes it easy to use that for substitution.

  3(-7y) +y = 20

  -20y = 20 . . . . . collect terms

  y = -1 . . . . . . . . . divide by -20

  -7(-1) = x = 7 . . . use y in the second equation to find x

The solution is (x, y) = (7, -1).

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