<span>y=4x-6
y=-4x+48
</span>4x-6= -4x+48
<span>0x=54
x=o</span>
The square root of 52
the third answer
Answer: 
Step-by-step explanation:
We know that the standard quadratic equation is ax^2+bx+c=0
Let's compare all the given equation to it and , find discriminant.
1. a=2, b= -7, c=-9
So it has 2 real number solutions.
2. a=1, b=-4, c=4

So it has only 1 real number solution.
3. a=4, b=-3, c=-1

So it has 2 real number solutions.
4. a=1, b=-2, c=-8
So it has 2 real number solutions.
5. a=3, b=5, c=3

Thus it does not has real solutions.
Sorry, I guess I was in a hurry. This is how I did it after carefully reading the problem.
9.54% times which mobile phone (the one we are looking for=y) would use 1.908
that is: 0.0954 times y=1.908
0.0954y=1.908 dividing each side by 0.0954, we get y=20
So, the answer is y=20, or the mobile phone is 20