We use x(t) to solve for t and substitute the answer in y(t):
Find t.
x = cos(t) + 5,
cos(t) = x - 5,
t = arccos(x-5).
We simply substitute in y(t).
y = 7sin(2arccos(x - 5)).
We can now use trig identities to transform this into algebraic equation
a) double angle formula first
y = 7 x 2 x sin(arccos(x - 5)) cos(arccos(x-5))
b) using sin(arccos(x)) = √(1 - x2) and cos(arccos(x)) = x, we get
y = 14 (x - 5)√(1 - (x - 5)2)
In case you have interpretation that 2 is an exponent, even simpler - use Pythagorean identity for sine and cosine:
y = 7sin2(arccos(x - 5))
y = 7[1 - cos2(arccos(x - 5))]
y = 7[ 1 - (x - 5)2]