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To solve this system by substitution, which variable in which equation should be isolated?

{(4x+5y=4),(2x+y=7):}
x in the first equation
y in the first equation
x in the second equation
y in the second equation

User Lemonina
by
8.3k points

2 Answers

2 votes

Answer:

I would go for y in the first equation

Explanation:

  1. Eliminating x and isolating y is easier
    4x + 5y = 4;
    2x + y = 7;
  2. Multiply both sides and eliminate x
    4x + 5y = 4;
    -2(2x + y) = -2(7)
    -4x -2y = -14;
  3. Combine the equations
    4x - 4x + 5y - 2y = 4 - 14
    3y = - 10
    y = (-10/3)

You get y from the first equation I guess. The question is a bit confusing though.

User Athanor
by
7.6k points
3 votes
X is the first variable to use for this equation
User Samkit Shah
by
8.5k points

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