X + y = 2 0 3x + 3y - 5 = 0

Step-by-step explanation:

step 1. let l be the length of the rectangle

step 2. l = 2x + 4

step 3. lx = 390 yd^2

step 4. (2x + 4)x = 390

step 5. 2x^2 +4x = 390

step 6. 2x^2 + 4x - 390 = 0

step 7. -4 +- sqr(4^2 -4(2)(-390))/2(2) quadratic formula

step 8. (-4 +- sqr(3136))/4

step 9. (-4 +- 56)/4

step 10. x = 13yd, l = 2x + 4 = 2(13) + 4 = 30yd.