# SOLUTION: a line through (-9,-9) and a slope of -7 has a y-intercept at what?

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 Click here to see ALL problems on Coordinate-system Question 227045: a line through (-9,-9) and a slope of -7 has a y-intercept at what?Answer by algebrapro18(206)   (Show Source): You can put this solution on YOUR website!Their are 2 ways to solve this problem. Method 1. Using the slope-intercept formula of a line. We know that the equation of a line in slope interecept form is y=mx+b where m is the slope and b is the y intercept. Since we have the slope and a point we could plug those in and solve for b. y = mx+b -9 = 7(-9)+b -9 = -63+b 54 = b So we know the y-intercept is at 54. Method 2. Using the point slope formula. There is another equation that will give us the equation of a line. Its y-y1=m(x-x1). Where (x1,y1) is the given point and m is your slope. Plugging in the values we have we get: y-(-9) = 7(x-(-9)) y + 9 = 7(x+9) y = 7x+63-9 y = 7x+54 SO we know that the y-intercept is 54. Either method you use will get you the right answer.