Without Graphing, is the System Independent, Dependent, or Inconsistent: 2x + y = 9 and 3x + 4y = 8?

To determine whether the system of equations is independent, dependent, or inconsistent, we can analyze the equations algebraically.

The given equations are:

  • 1) 2x + y = 9
  • 2) 3x + 4y = 8

First, we can express both equations in terms of one variable, say y.

From the first equation:

y = 9 – 2x

Now, substituting this expression for y into the second equation:

3x + 4(9 – 2x) = 8

This simplifies to:

  • 3x + 36 – 8x = 8
  • -5x + 36 = 8
  • -5x = 8 – 36
  • -5x = -28
  • x = rac{28}{5}

Now that we have a value for x, we can substitute it back to find y:

y = 9 – 2(28/5)

y = 9 – 56/5

y = rac{45}{5} – rac{56}{5}

y = - rac{11}{5}

Since we found a unique solution for both x and y, this means that the system of equations is independent. An independent system has exactly one solution, whereas a dependent system has infinitely many solutions, and an inconsistent system has no solution.

In conclusion, the system of equations 2x + y = 9 and 3x + 4y = 8 is independent.

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