If one root of the equation x² + px + 12 = 0 is 4, find the value of p.
A-7CORRECT
B7
C-4
D4
GCEMathematicsQuadratic Equations2022
AI
Toaster Teacher
Why the answer is A, and why the others tempt you.
Since x = 4 is a root, substituting gives 16 + 4p + 12 = 0, so 4p = -28, giving p = -7. The other root can be found as 12/4 = 3, and sum of roots = -(p) = 4 + 3 = 7, so p = -7.
Want this in Pidgin, Yoruba, Igbo or Hausa? Sign up free →
Practice more Mathematics questions
GCE Mathematics has thousands more questions like this — with Worked answers on every one.