Question 377678
No, it's not correct.
When {{{x=20}}},
{{{y = (3/10)(20-10)(20-30)}}}
{{{y=(3/10)(10)(-10)}}}
{{{y=-30}}}
and also,
When {{{x=0}}},
{{{y = (3/10)(0-10)(0-30)}}}
{{{y=(3/10)(-10)(-30)}}}
{{{y=90}}}