Which statement is true about the equation $-3(p+5)=2(p+2)+1$?


AThe only solution is $p=\frac{2}{5}$
BThere are infinitely many solutions
CThe only solution is $p=-4$
DThere is no solution

Verified Answer :

  • Expand both sides of the equation: \(-3p - 15 = 2p + 5\).
  • Move terms to isolate \(p\): \(-20 = 5p\).
  • Solve for \(p\): \(p = -4\).
  • The correct statement is: \(\boxed{\text{The only solution is } p = -4}\).

Explanation

  1. Analysis of the Equation

The given equation is \(-3(p+5) = 2(p+2) + 1\). We need to determine the value of \(p\) that satisfies this equation, or determine the nature of its solution set. This is a linear equation in one variable, \(p\). To find the solution, we will expand the expressions on both sides, simplify, and then isolate the variable \(p\).

  1. Expansion and Simplification

First, we expand the terms on both sides of the equation:
Left side: \(-3(p + 5) = -3p - 15\)
Right side: \(2(p + 2) + 1 = 2p + 4 + 1 = 2p + 5\)
Equating the expanded forms, we have:
\(-3p - 15 = 2p + 5\)

  1. Isolating the Variable p

To solve for \(p\), we gather all terms containing \(p\) on one side and the constant terms on the other:
Add \(3p\) to both sides: \(-15 = 5p + 5\)
Subtract 5 from both sides: \(-15 - 5 = 5p\)
\(-20 = 5p\)
Divide by 5: \(p = \frac{-20}{5} = -4\)

  1. Verification and Conclusion

We have found that the equation simplifies to \(p = -4\). Substituting \(p = -4\) back into the original equation to verify:
Left side: \(-3(-4 + 5) = -3(1) = -3\)
Right side: \(2(-4 + 2) + 1 = 2(-2) + 1 = -4 + 1 = -3\)
Since both sides are equal, the unique solution to the equation is \(p = -4\). Comparing this to the given options, the correct statement is that the only solution is \(p = -4\).

Examples

In daily life, solving for a single variable is useful for finding unknown quantities in budget planning or resource allocation. For example, if you are determining how many hours \(p\) you need to work to cover a cost, where the costs follow a linear relationship such as \(-3(p + 5) = 2(p + 2) + 1\), finding the correct value of \(p\) helps you manage your time and finances effectively. By isolating the variable, you can make informed decisions based on calculated data.