Question

what value of r is a solution to this equation? 72 = 3r + 5r r = -11 r = 9

Explanation:

Step1: Combine like terms

On the right side of the equation \(72 = 3r + 5r\), we combine the like terms \(3r\) and \(5r\). Since \(3r+5r=(3 + 5)r=8r\), the equation becomes \(72=8r\).

Step2: Solve for \(r\)

To solve for \(r\), we divide both sides of the equation \(72 = 8r\) by 8. So, \(r=\frac{72}{8}\). Calculating \(\frac{72}{8}\), we get \(r = 9\). We can also check by substituting \(r = 9\) into the original equation: left side is \(72\), right side is \(3\times9+5\times9=27 + 45=72\), which is equal. For \(r=- 11\), substituting gives \(3\times(-11)+5\times(-11)=-33-55=-88
eq72\).

Answer:

\(r = 9\)