Question

What is the equation of the line that passes through (1,2) and is parallel to the line whose equation is 2x+y-1=01. 2x-y-4=02. 2x+y-4=03. 2x+y+4=0

Answer 1

STEP - BY - STEP EXPLANATION

What to find?

Equation of a line.

Given:

Passes through point ( 1, 2)

Parallel to line 2x+ y - 1 =0

Step 1

Write the parallel line equation in slope - intercept form.

That is; In the form y=mx + b

`y=-2x+1`

Step 2

Determine the slope of the line.

Comparing the equation above with the general equation y=mx + b

`slope(m)=-2`

Step 3

Find the slope of the new equation.

Slope of parallel line are equal, hence slope(m) = -2

Step 4

Find the intercept(b) of the new equation by substituting (1,2) and m=-2 into y=mx + b

x=1 and y=2

Where b is the intercept.

`2=-2(1)+b`
`\begin{gathered} 2+2=b \\ \\ b=4 \end{gathered}`

Step 5

Form the new equation by substituting the value of m and b into y=mx + b.

`y=-2x+4`

Step 6

Re-arrange the equation.

`2x+y-4=0`

ANSWER

Second option

2x+y-4=0