I can help you with those, they're very easy. Those letters that you see are called variables. If the numbers you're solving have the same variables then you can add and subtract them normally. 15) 14y-7y= 7y 16) 3p+12p=15p 17) use distributive property, multiply the number outside the ( ) with the number inside of it, in this case only one number has a variable but with multiplication and division it doesn't matter. 2(3+5m)= 6+10m 18) 5(3x+2)= 15x+10
