8x-6y=-18 = y=4x/3 +3 and 8x+7y=9 is 8x/7+9/7
rationalise the denominator by multiplying both top and bottom by (8-5√3) then expand and simplify
Take 2points
Equation in two point form
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Option D is correct
I will assume you mistyped this question. For y = -1/16x^2 + 4x + 3, the answers to this question are
a) 3 feet
b) 67 feet
c) 64.741 feet
For a) we note that at x = 0, that is the instant where the ball leaves the hand. y(0) = 0.
For b), we find the vertex of y = -1/16x^2 + 4x + 3
y = -1/16x^2 + 4x + 3
y = -1/16(x^2 - 64x) + 3
y = -1/16(x^2 - 64x + 1024 - 1024) + 3
y = -1/16((x-32)^2 - 1024) + 3
y = -1/16(x-32)^2 + 64 + 3
y = -1/16(x-32)^2 + 67
The vertex is at (32,67) so 67 is the maximum height.
For c), we find the x-intercepts with the quadratic formula on
y = -1/16x^2 + 4x + 3=0:
x = [ -b ± √b^2 - 4ac ] / (2a)<span>
x = [ -4 ± √4^2 - 4(-1/16)(3) ] / (2(-1/16))
x = -0.741, 64.741
Only the positive solution, so 64.741 feet </span>
