B=-2, all of my steps and answer are listed in this pic
Answers + Explanation:
1. x + 7 =10
if you know some number + 7 is 10, you know that number must be 3.
so, x = 3
the other way you can solve this would be:
x + 7 = 10
subtract 7 from both sides of the equation
x + 7 - 7 = 10 - 7
x = 3
2. Use the same strategy:
x - 8 = -5
add 8 to both sides of the equation
x - 8 + 8 = -5 + 8
x = 3
3. x + 3 = 6
subtract 3 from both sides of the equation
x + 3 - 3 = 6 - 3
x = 3
4. x + 6 = 3
subtract 6 from both sides of the equation
x + 6 - 6 = 3 - 6
x = -3
Answer:

Step-by-step explanation:
The equation of a line in point-slope form is

where y1 and x1 are 2 known points, and m is the slope of the line. So simply just fill in the blanks.
y is a variable so it is left alone (since there is no subscript).
y1 we are told is 1.
m we are told is -3 (the slope)
x is a variable so it is left alone (since there is no subscript).
x1 we are told is 6.