Answer
a) $(1,5)$
b) In 1996, about 5% of households used wall or floor furnaces. Also, 5% of households used fireplaces or wood stoves.
c) Please see the graph. The percentage of households using fireplaces or wood stoves decreased faster than the percentage of households using wall or floor furnaces.
Work Step by Step
a)
$y=-.04x+5.1$
$y=-.31x+5.3$
$-.04x+5.1=-.31x+5.3$
$.27x = .2$
$.27x/.27 = .2/.27$
$x= .74$
$y=-.04x+5.1$
$y=-.04*.74+5.1$
$y=-.0296+5.1$
$y=5.0704$
$y=5.07$
c)
Red line: $y=-.04x+5.1$
Blue line: $y=-.31x+5.3$