When -2x+y=1 and y=-x+4, x = 1
We are given :

Step 1: factor the part inside square root
The function given inside square root is of quadratic form.
So let us try to factorise it using AC method.
Here A*C = 4*25 = 100
so we have to find factors of 100 that add up to give -20.
the two factors are -10 and -10.
Rewriting the function :

=
=
=
Step 2:
Now we take square root of the factorised form

= 
Answer : (2x-5)
What is the answer or this.
The correct answer is c. There is no possible way to know how much the mean age decreases, but we know it definitely will (averages decrease as values less than the average are added to the data.) <span />