Answer with explanation:
QUES 1)
Let x denote the gig of data used.
and y denote the monthly charge for use of data
We know that the equation of a line with given slope "m" and y-intercept "c" is given by:
y=mx+c
Runfast--
The monthly charge is: $ 8
and the cost of per gig of data is: $ 8
Since, the cost per gig represent the slope and fixed monthly charge represent the y-intercept.
Hence, the equation that is given by this set of information is:
BA & D--
The monthly charge is: $ 15
and the cost of per gig of data is: $ 4
Hence, the equation that is given by this set of information is:
QUES 2)
We will substitute the value of y from equation (1) in equation (2) as follows:
8x+8=4x+15
i.e. 8x-4x=15-8
i.e. 4x=7
i.e. x=7/4=1.75
and the value of y is:
y=8×1.75+8
i.e. y=22
Hence, the cost of both the companies are equal when 1.75 gigs of data is used and the cost is: $ 22
( Since , the solution is: (1.75,22) )