# Are my answers correct to these problems?

• Aug 27th 2009, 06:22 AM
yitsongg
Are my answers correct to these problems?
Write an equation for the given line:

1. P(2,3), m=2
2. P(1,0), no slope
3. P (-1,2), m=-1/2
4. P(2,3), m = 0

1.y=2(x-2)+3
2. y=(x-1)
3. y= -1/2(x+1)+2
4. y=(x-2)+3
• Aug 27th 2009, 06:49 AM
Haytham
no slope or m=0, means the line is horizontal, having the same y-value for all x

so it doesnt depends of x

2 and 4 arent correct
• Aug 27th 2009, 07:13 AM
VonNemo19
Quote:

Originally Posted by yitsongg
Write an equation for the given line:

1. P(2,3), m=2
2. P(1,0), no slope
3. P (-1,2), m=-1/2
4. P(2,3), m = 0

1.y=2(x-2)+3
2. y=(x-1)
3. y= -1/2(x+1)+2
4. y=(x-2)+3

The point-slope form of the equation to a line is given by \$\displaystyle (y_2-y_1)=m(x_2-x_1)\$.

The answer you have for the first problem is correct. In the second problem, however, your are asked to find the equation to a line that goes through the point \$\displaystyle (1,0)\$ that has no slope. No slope implies that the line is vertical. Thus, the equation is \$\displaystyle x=1\$.

Number 3 is correct.

Number 4 is wrong. If I use the formula that I have written at the beginning og this post, I have

\$\displaystyle y-3=0(x-2)\$
\$\displaystyle y-3=0\$
\$\displaystyle y=3\$

This is a horizontal line, as is expected given a slope of 0.
• Aug 27th 2009, 07:18 AM
yitsongg
Thanks