Question

1. b² - 9a

Explanation:

Step1: Identify common factor

The expression is \( b^2 - 9a \). Wait, maybe it's a typo? If it's \( b^2 - 9a^2 \), then we can factor it. Assuming it's \( b^2 - 9a^2 \) (difference of squares: \( x^2 - y^2=(x - y)(x + y) \)). Here \( x = b \), \( y = 3a \).

Step2: Apply difference of squares

\( b^2 - 9a^2=(b - 3a)(b + 3a) \)
But if the original is \( b^2 - 9a \), we can factor out \( b \)? Wait, no, \( b^2 - 9a = b^2 - 9a \), no common factor. But likely a typo, maybe \( b^2 - 9a^2 \). Let's proceed with \( b^2 - 9a^2 \).

Answer:

If the expression is \( b^2 - 9a^2 \), the factored form is \((b - 3a)(b + 3a)\). If it's \( b^2 - 9a \), it can't be factored further with integer coefficients.