# equation

posted by
**larry**
.

if the gas prices was say was .90 a gallon in 1950 and the prices now are 3.00 a gallon how would you write an equation to show the increase I am needing to graph this so i need a slope i think can anyone explain this please

There is no need to plot a graph for the slope. You have two points

X1=1950, y1=0.90

X2=2007, y2=3.00

gradient, m=(y2-y1)/(x2-x1)

This assumes a straight line. The equation of the line is

y=mx+c

If you need the equation as well, substitute one of the points [(x2,y2) or (x1,y1)] and m into the equation and find c.

what would be an equation if a person weigh 350 lbs and lost 20lbs a month and her weight now is 150 how would you write this as an equation

350=m*20+150

Yes, that works, where m is the number of months.

Might be clearer (?) as

350-m*20=150

how would i graph this to show the lose of weight within a twelve month period

y=mx+b

m being the slope would that be the 12 months

y being the start weight and x being the amount of weight lost