+78 Im assuming without a calculator;
well - lets turn \({3.806}^{2}\)
into \({(x+0.806)}^{2}\) where \(x=3\)
now we expand \(x^2 +2(0.806)+{(0.806)}^{2}\)
0.806\(\times\)0.806 is much easier to do than 3.806^2
\(0.806\times0.806 = \)
2((0.806 * 0.400)+(0.806 * 0.003))
2((0.32+0.0024)+(0.002418))
2(0.3224+0.002418)
2(0.324818)
0.649636
\(x^2+2(0.806)+0.649636\)
sub \(x=3\)
\((3)^2+2(0.806)+0.649636\)
\(9+1.612+0.649636\)
\(11.261636\)
ta dah!
