Does the point (3 , 25) lie on the line y = 6x + 7

Question

It's for homework and I don't really understand the question 

Answer 1

y = 6x + 7 is the equation of a line.  It is in slope-intercept form:  y=mx + b

    where m=slope and the point (0,b) is the y-intercept

 

The point with coordinates (3 , 25) means the point where x=3 and y=25 because we use the format (x,y) to express the coordinates for a point.

 

"Does the point (3 , 25) lie on the line y = 6x + 7" is true if 25=6(3)+7   [we just put the x and y from the point into the formula; any point with coordinates (x,y) that satisfies the equation is on the line.]

 

Note. for example, that the point with coordinates (5,2) is not on the line because 2≠6(5)+7.  It's all based on whether the formula is true or not for the coordinates of a point.

Answer 2

To see whether or not a point lies on a line in a y=mx+b equation, you must plug in your x value(in this case, 3) and see what your y value is. 

 

Let's try this:

 

y=6(3)+7=18+7=25

 

Because plugging in 3 to the equation gives a y value of 25, the coordinate (3,25) lies on the line.

Answer 3

Chloe,

 

Just plug the numbers in for x and y and see if the equation holds:

 

25 = 6*3 + 7 = 25

 

Yes