+118723 y varies inversely with x. y=40 x=16
find x when y=-5
\(y\;\alpha\; \frac{1}{x}\\ y\;= \frac{k}{x}\qquad \mbox{Where k is a constant}\\ \mbox{Sub in y=40 and x=16 to find k}\\ 40=\frac{k}{16}\\ k=40*16=640\\ so\\ y=\frac{640}{x}\\ \mbox{sub in y=-5}\\ -5=\frac{640}{x}\\ -5x=640\\ x=640/-5\\ x=-128\)
y=-5 when x=-128
