Solve the system by substitution: 3x + 10y = 31, 2x + 10 = y

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Understand the Problem

The question is asking us to solve a system of equations using the substitution method. We need to find the values of x and y that satisfy both equations provided.

Answer

$(-3, 4)$
Answer for screen readers

The solution to the system of equations is $(-3, 4)$.

Steps to Solve

  1. Solve for y in the second equation

From the second equation, we can express $y$ in terms of $x$:

$$ y = 2x + 10 $$

  1. Substitute y in the first equation

Now replace $y$ in the first equation with the expression we found:

$$ 3x + 10(2x + 10) = 31 $$

  1. Simplify the equation

Distribute $10$ in the equation:

$$ 3x + 20x + 100 = 31 $$

Combine like terms:

$$ 23x + 100 = 31 $$

  1. Isolate x

Subtract $100$ from both sides:

$$ 23x = 31 - 100 $$

Which simplifies to:

$$ 23x = -69 $$

Now divide by $23$:

$$ x = -3 $$

  1. Find y using x

Substitute $x = -3$ back into the equation we found for $y$:

$$ y = 2(-3) + 10 $$

This results in:

$$ y = -6 + 10 $$

Finally, we have:

$$ y = 4 $$

The solution to the system of equations is $(-3, 4)$.

More Information

The solution $(-3, 4)$ means that when $x = -3$, $y = 4$ are the values that satisfy both original equations simultaneously. This method demonstrates the substitution method, which is useful for solving linear systems efficiently.

Tips

  • Incorrect substitution: Ensure substitution is done accurately to avoid errors in the equations.
  • Combining terms incorrectly: Pay attention to combining like terms carefully, as mistakes can lead to incorrect results.

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