Xavier (x) has $20 more than Sara (s). Their combined money totals $90. Which system of equations represents this situation?
1 answer:
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Answer:
(0 , -a²)
Step-by-step explanation:
tangent at x = a and x = -a
y = x² (a , a²) and (-a , a²) must be on the curve and tangent to curve
gradient dy/dx = 2x
slope (m) at x = a is <u>2a</u> and slope (m') at x=-a is<u> -2a</u>
line1: (y - a²) / (x - a) = 2a
y - a² = 2a (x - a) y = 2ax - a² ... (1)
line2: (y - a²) / (x + a) = - 2a y = -2ax- a² ... (2)
(1) - (2): 4ax = 0 a≠0 x = 0
y = - a²
I wish I did it right, or ....
