You weigh 680 n.
what would you weigh if the earth were
seven times as massive as it is and its radius
were six times its present value?
answer in units of n.

132.22 N

Explanation:

Weight at the surface of a planet is:

W = GMm / r²

where G is the gravitational constant,

M is the mass of the planet,

m is the mass of the object,

and r is the radius of the planet.

On Earth:

680 N = GMm / r²

If Earth's mass and radius were changed:

W = G (7M) m / (6r)²

W = 7/36 GMm / r²

W = 7/36 (680 N)

W = 132.22 N

d.7.5cm is your answer