Equation of a Straight Line: Using the two given points

Examples with solutions for Equation of a Straight Line: Using the two given points

Exercise #1

Find the equation of the line passing through the two points (2,6),(4,12) (-2,-6),(4,12)

Video Solution

Step-by-Step Solution

In the first step, we'll find the slope using the formula:

m=y2y1x2x1 m=\frac{y_2-y_1}{x_2-x_1}

We'll substitute according to the given points:

m=12(6)4(2) m=\frac{12-(-6)}{4-(-2)}

m=186=3 m=\frac{18}{6}=3

Now we'll choose the point (4,12) and use the formula:

y=mx+b y=mx+b

12=3×4+b 12=3\times4+b

12=12+b 12=12+b

b=0 b=0

We'll substitute the data into the formula to find the equation of the line:

y=3x y=3x

Answer

y=3x y=3x

Exercise #2

Find the equation of the line passing through the two points (13,1),(13,2) (\frac{1}{3},1),(-\frac{1}{3},2)

Video Solution

Step-by-Step Solution

In the first step, we'll find the slope using the formula:

m=y2y1x2x1 m=\frac{y_2-y_1}{x_2-x_1}

We'll substitute according to the given points:

m=1213(13) m=\frac{1-2}{\frac{1}{3}-(-\frac{1}{3})}

m=123=32 m=\frac{-1}{\frac{2}{3}}=-\frac{3}{2}

Now we'll choose point (13,1) (\frac{1}{3},1) and use the formula:

y=mx+b y=mx+b

1=32×13+b 1=-\frac{3}{2}\times\frac{1}{3}+b

1=12+b 1=-\frac{1}{2}+b

b=112 b=1\frac{1}{2}

We'll substitute the given data into the formula to find the equation of the line:

y=32x+112 y=-\frac{3}{2}x+1\frac{1}{2}

Answer

y=32x+112 y=-\frac{3}{2}x+1\frac{1}{2}

Exercise #3

Find the equation of the line passing through the two points (5,0),(12,412) (5,0),(\frac{1}{2},4\frac{1}{2})

Video Solution

Step-by-Step Solution

First, we will use the formula to find the slope of the straight line:

We replace the data and solve:

(04.5)(50.5)=4.54.5=1 \frac{(0-4.5)}{(5-0.5)}=\frac{-4.5}{4.5}=-1

Now, we know that the slope is 1 -1

 

We replace one of the points in the formula of the line equation:

y=mx+b y=mx+b

(5,0) (5,0)

0=1×5+b 0=-1\times5+b

 0=5+b 0=-5+b

b=5 b=5

Now we have the data to complete the equation:

y=1×x+5 y=-1\times x+5

y=x+5 y=-x+5

Answer

y+x=5 y+x=5

Exercise #4

Find the equation of the line passing through the two points (9,10),(99,100) (9,10),(99,100)

Video Solution

Answer

y=x+1 y=x+1

Exercise #5

Find the equation of the line passing through the two points (2,8),(6,1) (2,8),(6,1)

Video Solution

Answer

y=134x+1112 y=-1\frac{3}{4}x+11\frac{1}{2}

Exercise #6

Find the equation of the line passing through the two points (12,40),(2,10) (12,40),(2,10)

Video Solution

Answer

y4=3x y-4=3x

Exercise #7

Find the equation of the line passing through the two points (15,36),(5,16) (15,36),(5,16)

Video Solution

Answer

y=2x+6 y=2x+6

Exercise #8

Find the equation of the line passing through the two points (5,11),(1,9) (5,-11),(1,9)

Video Solution

Answer

y+5x=14 y+5x=14