Question 293909
You could start with the slope-intercept form of a linear equation:{{{W = mF+b}}} where: W = weight of plane and F = amount of fuel in gallons.
The slope, m, of the function is given as: {{{m = 5.7}}} so you can substitute.
{{{W = 5.7F+b}}} You can find b, the W-intercept (or the weight of the plane with no fuel) by substituting the given fuel and weight amounts: W = 2367.9 and F = 47.
{{{2367.9 = 5.7(47)+b}}}
{{{b = 2100}}} so the final equation is:
{{{W = 5.7F+2100}}} Now you can find the weight, W, of the plane when it has 20 gallons of fuel (F=20) in its tank.
{{{W = 5.7F+2100}}} Substitute F = 20.
{{{W = 5.7(20)+2100}}}
{{{highlight(W = 2214)}}}lbs.