Which of the following values of x will result in an imaginary number for
√2x+7

x ≤ -4 will result in an imaginary number. (From the graph it's actually 3.5, so if you want to view in REAL number then it's x ≤ -3.5 which will result in imaginary numbers.)

But if you want an integer then It's x ≤ -4

Real Number as it's x ≤ -3.5

Volume of the pool is :393.75 cubic metres.

CHECK THE ATTACHEMENTS TOO.

HOPE IT HELPS.