First you move -15 over which makes it 7b=5b+12
then you move 5b over so then its 2b=12
divide b=6
Finding the slope using two points:
The formula for slope is
In this case...
^^^Plug these numbers into the formula for slope...

1
^^^This is your slope
Hope this helped!
~Just a girl in love with Shawn Mendes
Addition: 70 + 80 = 150. You round 65 up because the ones digit is greater than and the same with 77.
Multiplication: Round up since both ones digits are bigger than 5. 70 x 80= 5600.
One way is to type it into your trusty TI and use the table from presing stat and then stat againg then calc then 4
so the equation that I got from your set of points is y=1.983333333333333x+0.80555555555
Sum is the result of adding so
12 + x, but i don't see it as a option.