Simply and state any restrictions on the variables. Help please 1. m+7/m^2+4m-21
2. x^2-16/9-x•x^2+x-90/x^2+14x+40
3. 2b^2‐12b/b+5÷b-6/b+5​

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Find the missing variable for a parallelogram: a = latex: 32in^2 32 i n 2 h = b = 6.3 in (1in=2.54cm)

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?