Chapter 8.1, Problem 57CCR

To determine

The solution of the equation $4=7+p$ ,

Answer to Problem 57CCR

  $p=-3$

Explanation of Solution

Given:

The equation, $4=7+p$

Concept Used:

• To get rid of a number in addition from one side, subtract the same number from both sides of equal sign.
• To get rid of a number in subtraction from one side, add the same number both sides of equal sign.
• To get rid of a number in multiplication from one side, divide the same number from both sides of equal sign.
• To get rid of a number in division from one side, multiply the same number both sides of equal sign.

Rules of Addition/ Subtraction:

• Two numbers with similar sign always get added and the resulting number will carry the similar sign.
• Two numbers with opposite signs always get subtracted and the resulting number will carry the sign of larger number.

Rules of Multiplication/ Division:

• The product/quotient of two similar sign numbers is always positive.
• The product/quotient of two numbers with opposite signs is always negative.

Calculation:

In order to solve the given equation $4=7+p$ for the variable, isolate the variable term p on one side by performing some basic algebraic operations to get rid of the other numbers and terms associated with it.

Here to isolate p on right side, first subtract both sides by $7$ and then simplify further as shown below,

  $\begin{array}{c}4=7+p\\ 4-7=7+p-7\\ -3=p\\ \Rightarrow p=-3\end{array}$

Thus, the solution of the given equation is $p=-3$ .