Hi! I'm lazy but I'll explain number two so you get the concept. 2x + y =10
Well, It says x = 5. When a number is next to another number like this: 5(6), it means multiplication. Same when a number and a letter are together like this: 2x. So that means it's 2 times 5, since 5 = x. 2 times 5 is 10. So what plus 10 equals 10 (10 + y = 10) The answer now is obviously 0. So that's how you do those equations! Hope u understand lol :>
