In a rectangle, the 2 widths are equal and the 2 lengths are equal.
7x + 4 = 3y - 2...subtract 3y from both sides, subtract 4 from both sides
7x - 3y = - 6
4x = y + 3....subtract y from both sides
4x - y = 3
4x - y = 3.......-y = -4x + 3....y = 4x - 3...so we sub in 4x - 3 in for y in the other equation.
7x - 3y = -6
7x - 3(4x - 3) = -6
7x - 12x + 9 = -6
-5x = -6 - 9
-5x = - 15
x = -15/-5
x = 3
4x - y = 3
4(3) - y = 3
12 - y = 3
-y = 3 - 12
-y = - 9
y = 9
so x = 3 and y = 9
so the widths are :
4x.....4(3) = 12...............y + 3.....9 + 3 = 12
and the lengths are :
3y - 2.....3(9) - 2 = 25............7x + 4.....7(3) + 4 = 25
A = L * W
A = 25 * 12
A = 300 <== area
P = 2(L + W)
P = 2(25 + 12)
P = 2(37)
P = 74 <== perimeter
