Question 455382
First, you know that parallel lines have the same slope.
Second, get the given equation into slope-intercept form.
x +2y = 3
2y = -x +3
y = -x/2 +3/2
So, the slope = -1/2.
The y-intercept = 3
The x-intercept is where y=0, so that's x=3.
A graph is useful.
{{{graph(500,500,-10,10,-10,10,-1/2*x+3/2)}}}
.
But that line does not go through (7,9).
.
So, we have to find the value for b that will shift the line up or down to go through (7,9).
9 = -1/2*7 + b
Multiply though by 2
18 = -7 + 2b
25 = 2b
2b = 25
b = 25/2
which means the equation is
y = -x/2 + 25/2
Again, a graph is useful.
{{{graph(500,500,-15,15,-15,15,-1/2*x+3/2,-x/2+25/2)}}}