What is the equation of the line that has a slope of -3 and passes through the point (4,-2)
1 answer:
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Answer:
Equation of a line:
m = gradient: The difference between two y points and two x points.
c = y-intercept: Where the line crosses the y-axis (x=0)
You have:
so you are missing the m and the c.
To calculate m find two y coordinates -you have (12, <u>7</u>) and (0, <u>1</u>)- and subtract them. Then divide this by the subtracted values of the x coordinates -you have (<u>12</u>, 7) and (<u>0</u>, 1)- This gives:
To calculate the c, you just see where the line crosses the y-axis. Because you have the point (0, 1), you know that when x=0, y=1. Because x=0 is on the y-axis, you can tell that the line passes through y=1. This makes your c = 1:
When you plug these values into the equation you get your answer:
m = gradient: The difference between two y points and two x points.
c = y-intercept: Where the line crosses the y-axis (x=0)
You have:
so you are missing the m and the c.
To calculate m find two y coordinates -you have (12, <u>7</u>) and (0, <u>1</u>)- and subtract them. Then divide this by the subtracted values of the x coordinates -you have (<u>12</u>, 7) and (<u>0</u>, 1)- This gives:
To calculate the c, you just see where the line crosses the y-axis. Because you have the point (0, 1), you know that when x=0, y=1. Because x=0 is on the y-axis, you can tell that the line passes through y=1. This makes your c = 1:
When you plug these values into the equation you get your answer: