Problem
c. $9 a^{2}-42 a b+49 b^{2}$
Solution
Step 1 ：Given the expression: \(9a^2 - 42ab + 49b^2\)
Step 2 ：Factorize the expression: \((3a - 7b)^2\)
Step 3 ：\(\boxed{(3a - 7b)^2}\) is the simplified expression.
Step 1 ：Given the expression: \(9a^2 - 42ab + 49b^2\)
Step 2 ：Factorize the expression: \((3a - 7b)^2\)
Step 3 ：\(\boxed{(3a - 7b)^2}\) is the simplified expression.
