Answer:
(-5, 50) and (-1/3, -0.815)
Step-by-step explanation:
The equation is;
y = x³ + 8x² + 5x
Now the turning point will occur at where dy/dx = 0.
Thus;
dy/dx = 3x² + 16x + 5
At dy/dx = 0, we have;
3x² + 16x + 5 = 0
From quadratic formula, we can get;
x = -5 or -⅓
Thus, let's find y at this points.
y = -5³ + 8(-5)² + 5(-5)
y = -125 + 200 - 25
y = 50
Also,at x = -⅓, we have;.
y = (-⅓)³ + 8(-⅓)² + 5(-⅓)
y = -1/27 + 8/9 - 5/3
y = -0.815
Thus,the coordinates of the turning points are;
(-5, 50) and (-1/3, -0.815)
