Question 359491
one side of a rectangle is three feet more than half as long as the other side and the perimeter is 21 feet what are the dimensions of the rectangle.

Let x, y be the sides of the rectangle.
{{{y = (1/2)x+3}}}, and {{{2x+2y = 21}}}.
By substitution,
{{{2x + 2*((1/2)x+3) = 21}}},
{{{2x+x+6 = 21}}},
{{{3x = 15}}},
{{{x = 5}}}.