What is the equation of the line in standard form that passes through the point (3, 4) and is parallel to the line y = -x + 6?

Question

What is the equation of the line in standard form that passes through the point (3, 4) and is parallel to the line y = -x + 6?Choose one answer. Please just give me an explanation and the ANSWER. I just need to check my own. 

A. x + y = 1
 

B. x + y = 7
 

C. x - y = -1
 

D. x - y = -7

Answer 1

First you need to know that two lines that are parallel always have equal slopes. 

 

so, what is the slope of the line y = -x +6? It is equal to -1

 

now you can use y = mx + b, and substitute the ordered pair values to solve for b: 

 

4 = -1(3) + b 

 

so, b = 7 

 

now we can write the equation in y intercept form: 

 

y = -x + 7 

 

standard form is ax + by = c; so we need to move the x term to the other side:

to get x + y = 7 or choice B