Switch y=2x+7 to 2x-y=-7 then multiply that equation by 2 to cancel out the y's. that ends up as 4x-2y=-14 which then you get x=-24. then you substitute x into one of the original equations y= 2(-24)+7 which equals y=-41
I wrote it out on paper and uploaded the answer for you. Let me know if you have any questions.
To find Ken's speed divide total distance by total time:
174 miles / 3 hours = 58 miles per hour.
In the equation for Brenda, the 57 is the miles per hour because you would multiply that by x ( hours) to get total miles (y).
Ken had the faster driving speed.
So the formula to workout the area of a rectangle is height X width
so 11/3 x 5/8
which is 55/24 ft if they want a mixed number then... 2 
hope this helps