Who can help me wit algebra 9th grade?

Anormally distributed data set has a mean of 176.3 and a standard deviation of 4.2. what is the approximate z-score for the data value of 167.9? 2.00 −2.00 8.4 −8.4

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.

3.4a=57.8 what is the the value of a