Question 985669
a. 
{{{ 12x - 5x^2 }}}
What is the maximum value of this expression?
Without calculus:
f(x) = -5x^2 + 12x
The max is the vertex at x = -b/2a = -12/-10 = 1.2
f(1.2) = 14.4 - 7.2
= 7.2
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b. 
{{{ y = 4x^2 + x - 2 }}}
For which values of y will x be positive?
Find where y = 0
*[invoke solve_quadratic_equation 4,1,-2]
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x = 0 at those 2 points, x1 & x2
y is positive for x < x1 and x > x2