S$6-13$ Write a cost equation given regression output $($Learning Objective $5)$

A legal firm wanted to determine the relationship between its monthly operating costs and a potential cost driver, professional hours. An excerpt from the output of a regression analysis performed using Excel showed the following information:

$\backslash$table$[[,,,$c$,$D$,$E$,$F$,$G$],[$J$,$SUMMARY OUTPUT,,,,$],[2,,,,],[2,,,,,,,],[3,$Multiple R$,0\mathrm{.}92,,,,],[4,$R Square,$0\mathrm{.}81,,,,],[5,$Adjusted R Square,$148\mathrm{.}38,,,,],[6,$Standard Error,$148\mathrm{.}38,,,,],[7,$Observations,$12,,,,],[8,$ANOVA,,,,,Significance F$,],[9,$df$,55,$M$73,116\mathrm{.}90,$F $26\mathrm{.}03,0\mathrm{.}00,],[10,$Regression,$1,573,116\mathrm{.}90,573,116\mathrm{.}90,26\mathrm{.}03,,],[11,$Residual,$10,110,083\mathrm{.}10,22,016\mathrm{.}62,,,],[12,$Total,$11,683,200,00,,,,],[13,,,,,,],[14,,$Standard,,,Lower,Upper$],[15,$Coefficients,Error,tStat,P$-$value,$95\%,95\%],[16,$Intercept,$1,263\mathrm{.}34,806\mathrm{.}85,1\mathrm{.}57,0\mathrm{.}18,-810\mathrm{.}75,3,337\mathrm{.}42],[17,$X Variable $1,0\mathrm{.}26,0\mathrm{.}05,5\mathrm{.}10,0\mathrm{.}00,0\mathrm{.}13,0\mathrm{.}39],[18,,,,,,,]]$

a$.$ Given this output, write the legal firm's monthly cost equation.

b$.$ Should management use this equation to predict monthly operating costs? Explain your answer.