Question 25784
Well, you are on the right track!
Your answer should be in the form of y = mx + b as you have correctly stated but given the slope (m=-7/5) and  x-intercept of 5 allows you to calculate the y-intercept, b, which what you need for your equation.
A key point here is recognising that having an x-intercept of 5 means that x = 5 when y = 0.
So, starting with y = mx + b and substituting y = 0, x = 5, and m = -7/5, you can solve for b.

{{{y = mx + b}}}
{{{0 = (-7/5)(5) + b}}} Simplify and solve for b.
{{{0 = -7 + b}}} Add 7 to both sides of the equation.
{{{7 = b}}} Now you can write your equation.

{{{y = (-7/5)x + 7}}}