Answer:
I'm not sure but try 13.5.
Step-by-step explanation:
It might not be correct sorry
Let the unknown number be x.
x × -7 = 7 (x + -40)
-7x = 7x - 280
-14x = -280
x = 280/14
x = 20
Hope this helps!
Answer:
12 cm
Step-by-step explanation:
The Pythagorean Theorem is as follows:

A and B represent the side lengths (legs) and C represents the hypotenuse.
The length of one leg equals 5cm. (This can be represented by either a or b)
The hypotenuse equals 13 cm.
Plug these into the equation from above:

Solve for the other leg:
Square what's in the parentheses from above
Subtract 25 from 169
Square root both sides
a = 12 cm
Thus, the length of the other leg is 12 cm.
Let's check our answer:
Square everything
144 + 25 = 169 Add
169 = 169
Because both sides are equal it means that 12 cm is the correct answer.
Hope this helps!!
It's the inverse operation of squaring that number. It's an odd definition to explain lol