Answer:
4.618
Explanation:
Let's use x to represent the number so we can write an equation to solve it.
'twice the number' is represented by 2x so we have our equation:
2x-5^0.5=7
(5^0.5 is just square root 5 because I can't do a square root symbol.)
Now we need to isolate the x term so:
2x-5^0.5+5^0.5=7+5^0.5
2x=7+5^0.5
Square root 5 = 2.236 (3dp)
2x=7+2.236
2x=9.236
2x/2=9.236/2
x=4.618
Hope this helped!