Question 10809
Let the length of the three equal-length pieces be x and the length of the fourth piece be y.

3x + y = 58
x = 3y-4 Substitute this x into the 1st equation.

3(3y - 4) + y = 58 Simplify and solve for y.
9y - 12 + y = 58
10y - 12 =58
10y = 70
y = 7

x = 3y-4
x = 3(7)-4
x = 21-4
x = 17.