Question

b) -9·b = 45

Explanation:

Step1: Isolate the variable \( b \)

To solve for \( b \) in the equation \( -9 \cdot b = 45 \), we divide both sides of the equation by \( -9 \). This is based on the property of equality that states if we divide both sides of an equation by the same non - zero number, the equation remains true.
The equation becomes \( \frac{-9\cdot b}{-9}=\frac{45}{-9} \)

Step2: Simplify both sides

Simplifying the left - hand side, \( \frac{-9\cdot b}{-9}=b \) (because a non - zero number divided by itself is 1, and \( 1\times b = b \)).
Simplifying the right - hand side, \( \frac{45}{-9}=- 5 \) (since a positive number divided by a negative number gives a negative result, and \( 45\div9 = 5 \)).

Answer:

\( b=-5 \)