Let m = 2x + 3. Which equation is equivalent to (2x + 3)^2 – 14x - 21 = -6 in terms of m?

a)m^2+7m+6=0
b)m^2+7m-15=0
c)m^2-7m-15=0
d)m^2-7m+6=0​

Jabari is power washing houses for a summer job. for every job, he charges an initial fee plus $30 for each hour of work. his total fee for a 4 -hour job, for instance, is $170 . jabari's total fee,f, for a single job is a function of the number,t, of hours it takes him to complete the job. write the function's formula.

Sarah used her calculator to find sin 125 degrees. she wrote down sin sin125 degrees.57. how could sarah recognize that her answer is incorrect?

We just started the introduction into circles and i have no idea how to do this.