Question

Help please!
Differentiate y = x^2 + bx + c, and hence find b and c
when x = 3 the gradient is 5, and x = 2 is a zero,

Answer 1

\[\frac{ dy }{ dx } = 2x + b \]
When \[x = 3, \frac{ dy }{ dx } = 5\]

So we get \[5 = 6 + b\] \[\rightarrow b = -1\]

\[x^2 + bx + c = 0 \rightarrow (2)^2 +(-1)(2) + c = 0 \rightarrow c = -2\]

Answer 2

oh i get how you did it now :D thanks!!