Question

There are two numbers whose sum is 50. Three times the first is 5 more than twice the second. What are the numbers?

Answer 1

Just carefully follow the words and turn them into math expressions and relationships. Since there are 2 numbers,

Let x = the first number
Let y = the second number

x + y = 50 since their sum is stated as 50. BTW, at this point we don't know which is the bigger number.
3x = 5 + 2y decode "is" as the = sign, and "5 more" as adding 5.

No solve these simply by addition by first rearranging the equations and multiplying the first by 2
2x + 2y = 100 doesn't change the equation since you multiplied both sides of the equal sign
3x - 2y = 5 to align the y terms so they drop out when both equations are added
5x = 105 and x = 105/5 = 21 then use the simple original equation (x + y = 50) to get y
3 + y = 50 so y = 50 - 21 = 29

Hence, x = 21 is the smaller number, and y = 29 are the 2 numbers that solve the problem