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y varies partly as the square of x and partly as the inverse...

y varies partly as the square of x and partly as the inverse of the square root of x.Write down the expression for y if y = 2 when x = 1 and y = 6 when x = 4

A.

y = 10x231+5231x

B.

y = x2 + 1x

C.

y = x2 + 1x

D.

y = x231+131x

Correct answer is A

y = kx2 + cx

y = 2when x = 1

2 = k + c1

k + c = 2

y = 6 when x = 4

6 = 16k + c2

12 = 32k + c

k + c = 2

32k + c = 12

= 31k + 10

k = 1031

c = 2 - 1031

= 621031

= 5231

y = 10x231+5231x