Answer:
+ 9
Step-by-step explanation:
Given the expression is a perfect square of the form
(ay + b)² = a²y² + 2aby + b² = 49y² + 42y +
Comparing coefficients of like terms
a² = 49 ( take the square root of both sides )
a = [tex]\sqrt{49}[/tex] = 7
2ab = 42 ( divide both sides by 2 )
ab = 21 , then
7b = 21 ( divide both sides by 7 )
b = 3, thus
b² = 3² = 9
Hence
49y² + 42y + 9 = (7y + 3)²
