Q. For the function f(x)=x2+5x−9, find the slope of the secant line between x=−7 and x=4.Answer:
Slope Formula: To find the slope of the secant line between two points on a function, we use the formula for slope, which is the change in y-values divided by the change in x-values. This is also known as the difference quotient and is given by x2−x1f(x2)−f(x1), where x1 and x2 are the x-values of the two points.
Find f(−7): First, we need to find the y-value when x=−7 by substituting −7 into the function f(x). So, f(−7)=(−7)2+5(−7)−9.
Calculate f(−7): Calculating f(−7) gives us f(−7)=49−35−9=5.
Find f(4): Next, we need to find the y-value when x=4 by substituting 4 into the function f(x). So, f(4)=(4)2+5(4)−9.
Calculate f(4): Calculating f(4) gives us f(4)=16+20−9=27.
Identify Two Points: Now we have the two points on the function: (−7,5) and (4,27). We can use these to find the slope of the secant line.
Calculate Slope: The slope of the secant line is (f(4)−f(−7))/(4−(−7))=(27−5)/(4+7).
Final Result: Calculating the slope gives us (22)/(11)=2.