Answer:
$393.60
Step-by-step explanation:
y'=dy/dx=d/dx(4x³+3x²-2x+9)
=(3*4x^(3-1)+2*3x^(2-1)-2*1x^(1-1)+9*0
y'=12x²+6x-2
Ok so QR=10 because x=5 and the bisector I believe is LM :)