Question 66145
{{{y = mx + b}}} is the slope-intercept form of a straight line
The y-intercept occurs when x=0
The x=intercept occurs when y=0
You say that the slope is known and the x-intercept is known
m is the slope, so lets say ({{{m = m[1]}}})
The x-intercept is at ({{{x[1], 0}}})
{{{y = mx + b}}}
When y=0,
{{{0 = m[1]x[1] + b}}}
{{{b = -m[1]x[1]}}}
So, the equation of the line becomes
{{{y = m[1]x - m[1]x[1]}}}
Let's try an example
m[1] = -1
x[1] = 7
{{{y = m[1]x - m[1]x[1]}}}
{{{y = -x - (-1)*7}}}
{{{y = -x + 7}}}
When y=0, x=7 as it should
When x =0 y = 7 also