Angles in a triangle total 180°
180=128+5x+10+9x
180-128-10=5x+9x
42=14x
x=3
14-4x=2y
divide both sides by 2
7-2x=y
subsitute 7-2x for y
7-2x+2x=7
add like terms
7=7
true
therefor these 2 equations are the same and there are an infinite number of equations
answer is C
To get the extrema, derive the function.
You get y' = 2x^-1/3 - 2.
Set this equal to zero, and you get x=0 as the location of a critical point.
Since you are on a closed interval [-1, 1], those points can also have an extrema.
Your min is right, but the max isn't at (1,1). At x=-1, you get y=5 (y = 3(-1)^2/3 -2(-1); (-1)^2/3 = 1, not -1).
Thus, the maximum is at (-1, 5).
