21/4 plus 7/8 equals need the answer quick

What is the common difference for this arithmetic sequence? -6,-2,2,6,10 a.4 b.5 c.3 d.6

Let f of x equals the integral from 1 to 3 times x of the natural logarithm of t squared. use your calculator to find f″(1).

The function below is written in vertex form or intercept form. rewrite them in standard form and show your work. y = (x+4)(x+3)