Step-by-step explanation:
The digital root of a number is the single digit that you get by adding all of the digits of the original number together. If the result of that is multiple digits, you add those digits together, repeating the process until you get a single digit. That digit is the digital root of the original number.
example given
257520643
2+5+7+5+2+0+6+4+3
7+12+2+10+3
7+1+2+2+13
8+4+1+3
8+4+4
12+4
16
1+6=7
Step-by-step explanation:

9999 is largest 4 digit number, and 100^2 is 10000, or 1 greater than the largest 4 digit number. This means that the closest square root of the largest perfect square is most likely 99. So 99^2 (9801)is the largest perfect square of four digits.
Answer:
Expanded:x²-7x+4x-28
Simplified: x²-3x-28
Step-by-step explanation: