7. Let g(x)=k2x2−10kx+6k+1, where k is a positive constant. The graph of y=g(x) passes through (2,9).(a) Find k.(b) How many x-intercept(s) does the graph of y=−g(x)+5 have?
Q. 7. Let g(x)=k2x2−10kx+6k+1, where k is a positive constant. The graph of y=g(x) passes through (2,9).(a) Find k.(b) How many x-intercept(s) does the graph of y=−g(x)+5 have?
Plug and Simplify Equation: Since the graph of y=g(x) passes through (2,9), we plug x=2 and y=9 into the equation g(x)=k2x2−10kx+6k+1. So, 9=k2(2)2−10k(2)+6k+1.
Combine Like Terms: Simplify the equation: 9=4k2−20k+6k+1.
Set Equation to Zero: Combine like terms: 9=4k2−14k+1.
Factor Quadratic Equation: Subtract 9 from both sides to set the equation to zero: 0=4k2−14k−8.
Solve for k: Factor the quadratic equation: (2k+1)(2k−8)=0.
Find X-Intercepts: Set each factor equal to zero and solve for k: 2k+1=0 or 2k−8=0.
Substitute k into g(x): Solve the first equation: 2k+1=0 leads to k=−21, which we discard because k is a positive constant.
Set Equation to Zero: Solve the second equation: 2k−8=0 leads to k=4.
Simplify Equation: Now we have the value of k, which is 4. Next, we find the number of x-intercepts for y=−g(x)+5.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.Now set −g(x)+5=0: −16x2+40x−25+5=0.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.Now set −g(x)+5=0: −16x2+40x−25+5=0.Simplify the equation: y=00.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.Now set −g(x)+5=0: −16x2+40x−25+5=0.Simplify the equation: y=00.Divide the equation by y=01 to make it simpler: y=02.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.Now set −g(x)+5=0: −16x2+40x−25+5=0.Simplify the equation: y=00.Divide the equation by y=01 to make it simpler: y=02.Use the discriminant y=03 to determine the number of x-intercepts. Here, y=05, y=06, and y=07.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.Now set −g(x)+5=0: −16x2+40x−25+5=0.Simplify the equation: y=00.Divide the equation by y=01 to make it simpler: y=02.Use the discriminant y=03 to determine the number of x-intercepts. Here, y=05, y=06, and y=07.Calculate the discriminant: y=08.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.Now set −g(x)+5=0: −16x2+40x−25+5=0.Simplify the equation: y=00.Divide the equation by y=01 to make it simpler: y=02.Use the discriminant y=03 to determine the number of x-intercepts. Here, y=05, y=06, and y=07.Calculate the discriminant: y=08.Simplify the discriminant: y=09.
Calculate Discriminant: The x-intercepts occur where y=0. So we set −g(x)+5=0.Substitute k=4 into g(x) to get g(x)=42x2−10(4)x+6(4)+1.Simplify g(x): g(x)=16x2−40x+25.Now set −g(x)+5=0: −16x2+40x−25+5=0.Simplify the equation: y=00.Divide the equation by y=01 to make it simpler: y=02.Use the discriminant y=03 to determine the number of x-intercepts. Here, y=05, y=06, and y=07.Calculate the discriminant: y=08.Simplify the discriminant: y=09.Since the discriminant is greater than −g(x)+5=00, there are −g(x)+5=01 real and distinct x-intercepts.