# Equation of the line

• Jan 25th 2010, 04:38 AM
Mist
Equation of the line
How do you solve this?

The line \$\displaystyle y= 4x+8 \$ meets the y-axis at the point B. Find the equation of the line with gradient 2 that passes through the point B.

Spoiler:
\$\displaystyle y=4x+8\$
\$\displaystyle 4x+8=0\$
\$\displaystyle 4x=8 \$
\$\displaystyle x=2\$

totally confused
• Jan 25th 2010, 04:51 AM
If x=0, then y=0+8=8.
Therefore (0,8) is the y-axis crossing point.

A line with gradient 2, passing through this point is \$\displaystyle y=2x+8\$

The gradient is called "m" as it is the multiplier of x
when the linear equation is expressed in the form y=mx+c.
• Jan 25th 2010, 04:56 AM
Raoh
Quote:

Originally Posted by Mist
How do you solve this?

The line \$\displaystyle y= 4x+8 \$ meets the y-axis at the point B. Find the equation of the line with gradient 2 that passes through the point B.

Spoiler:
\$\displaystyle y=4x+8\$
\$\displaystyle 4x+8=0\$
\$\displaystyle 4x=8 \$
\$\displaystyle x=2\$