We have that x²<span> + 7x + c </span><span>Group
terms that contain the same variable </span>(x² + 7x )+ c <span>Complete
the square. Remember to balance the equation </span>(x² + 7x+3.5² )+ c-3.5²
Rewrite as perfect squares
(x+3.5)²+ c-3.5² so c-3.5² must be zero c-3.5²=0------- c=3.5²------> c=12.25
