4x°=75-x° this might be wrong but I’m sure
B = 2A/h
The way you would get this is first by clearing the fraction. So in order to clear the fraction, you have to multiply the equation by the denominator.
2(A = 1/2bh)
2A = 1bh
2A = bh
Then you have to isolate the variable. So you'd divide bh by h in order to get b by itself. So you'd end up with:
2A/h = bh/h
2A/h = b
This is a simple Pythagorean Theorem problem. 7 is the hypotenuse so you would do c^2-a^2=b^2. In this case 7^2-2^2=b^2. 7^2 is 49 and 2^2 is 4 so you have 49-4=b^2. 49-4 is 45. The square root of 45 is 6.70. So x=6.70
She could give everyone an attendance sheet to mark down how much time it took them to read each week. i hope this answer has come to you pleasing