Final answer:
The value of s is 31/4 or approximately 7.75.
Step-by-step explanation:
To find the value of s, we need to use the formula for slope: m = (y2 - y1) / (x2 - x1). Using the given points (–7, s) and (–8, –7), we can substitute the values into the formula and solve for s. Since the slope is given as –3, we get: -3 = (-7 - s) / (-8 - (-7)). Cross-multiplying and simplifying the equation, we get -24 + 3s = 7 - s. Combining like terms, we have 4s = 31. Dividing both sides by 4, we find that s = 31/4, which is approximately 7.75.