Try graphing it to help, but since it's not a slanted line (because the y-values are the same), you just do x1-x2:
-3 - -7 = 4
It’s a right angle triangle so u have it use Pythagorean theorem.
c^2 = a^2 + b^2
25^2 = 20^ 2 + b^2
625 = 400 + b^2
b^2 = 225
b = 15
X = 15
According to your question, there are 2 unknown numbers mentioned.
Let the 2 unknown numbers be represented by the variables x & y, then
x is considered to be one of the numbers being more than y by the addition of 4, .ie.
x = 4 + y --- (1)
The sum of the 2 numbers is 60, i.e.
x + y = 60 --- (2)
To find the smaller number, we solve eqn (1) & (2) using the concept of substitution, i.e. substitute 4 + y for x in eqn (2), i.e.
4 + y + y = 60
4 + 2y = 60
2y = 60 - 4
2y = 56
y = 28 ...Ans.
Recall that x is more than y by 4, then 28 is the smaller number.