Answer:
x² + 4x - 21
Explanation:
Given the solutions of x = 3 and x = -7, moving the constant to the other side and setting both equations equal to '0':
x - 3 = 0 and x + 7 = 0
So, the two binomials that make up the quadratic are:
(x - 3)(x + 7)
Use FOIL: x² + 7x - 3x - 21
Combine like terms: x² + 4x - 21