+0

# algebra

0
249
2
+27

The sum of an even number and its square is 240. What is the number?

May 25, 2021

#1
+177
+1

-16+256=240 so it is -16.

May 25, 2021
#2
0

x = number      x^2 = square of number

x^2 + x = 240

x^2 + x - 240 = 0

Use Quadratic formula with    a = 1    b=1    c = -240

$$x = {-b \pm \sqrt{b^2-4ac} \over 2a}$$

and you will find  x = -16   or +15 (throw out...not even)

Check :  ( -16)^2 + -16 = 240        Check !

May 25, 2021