Question

solve: 13x = 91
a x = 7
b x = 9
c x = 78
d x = 104

Explanation:

Step1: Isolate the variable \( x \)

To solve for \( x \) in the equation \( 13x = 91 \), we divide both sides of the equation by 13. This is because in the term \( 13x \), \( x \) is being multiplied by 13, and to reverse the multiplication operation, we use division. The formula for this step is:
\[
\frac{13x}{13}=\frac{91}{13}
\]

Step2: Simplify both sides

Simplifying the left - hand side, \( \frac{13x}{13}=x \) (since 13 divided by 13 is 1). For the right - hand side, we calculate \( \frac{91}{13} \). We know that \( 13\times7 = 91 \), so \( \frac{91}{13}=7 \).

Answer:

A. \( x = 7 \)