Answer
$x=1.7, 4.3$
Tuesday, Thursday
This agrees with the graph.
Work Step by Step
$f(x)=3x^2-18x+57$
$f(x)=35$
$35=3x^2-18x+57$
$0=3x^2-18x+22$
$x=(-b±\sqrt {b^2-4ac})/2a$
$x=(-(-18)±\sqrt {(-18)^2-4*3*22})/2*3$
$x=(18±\sqrt {324-12*22})/6$
$x=(18±\sqrt {324-264})/6$
$x=(18±\sqrt {60})/6$
$x=(18±7.75)/6$
$x=(18±7.75)/6$
$x=(18+7.75)/6$
$x=25.75/6$
$x=4.291$
$x=(18±7.75)/6$
$x=(18-7.75)/6$
$x=10.25/6$
$x=1.708$
$x=1.7, 4.3$
