1. Plug in the y= problem to 2x problem. You should get 2x + 10x = 12, 2x + 10x is 12x so the new problem is 12x = 12 divide both sides by 12 and x = 1. Now, plug 1 in for x in y=10x which 10 x 1 = 10 so y is 10. X = 1, Y = 10
2. Same steps different numbers and you plug in x this time instead of y. So, y + 1 + 3y = 9, simplified is 4y + 1 = 9, subtract 1 form both sides. 4y = 8. Divide both sides by 4, y = 2. Plug y in, x = 2 + 1, x = 3. X = 3, Y =2