Question

find the missing number so that the equation has infinitely many solutions.
□x + 15 = -2x + 15

Explanation:

Step1: Recall infinite solutions condition

For an equation \(ax + b = cx + d\) to have infinitely many solutions, we need \(a = c\) and \(b = d\).

Step2: Apply to given equation

The given equation is \(\square x + 15=-2x + 15\). Comparing the coefficients of \(x\), we need \(\square=-2\) (since the constant terms \(15 = 15\) are already equal).

Answer:

\(-2\)