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What is the equation in slope-intercept form of the line that crosses the x-axis at 21 and is perpendicular to the line represented by y = 7/2x-13

Sagot :

Given:

A line is perpendicular to the line [tex]y=\dfrac{7}{2}x-13[/tex].

The line passes through the x-axis at 21.

To find:

The equation of the line in slope intercept form.

Solution:

The slope intercept form of a line is:

[tex]y=mx+b[/tex]

Where, m is the slope and b is the y-intercept.

The given line is:

[tex]y=\dfrac{7}{2}x-13[/tex]

So, the slope of this line is [tex]\dfrac{7}{2}[/tex].

The product of slopes of two perpendicular lines is -1.

Let m be the slope of required line. Then the slope of the required line is:

[tex]m\times \dfrac{7}{2}=-1[/tex]

[tex]m=-\dfrac{2}{7}[/tex]

The line passes through the x-axis at 21. It means the line passes through the point (21,0). So, the equation of the line is:

[tex]y-y_1=m(x-x_1)[/tex]

[tex]y-0=-\dfrac{2}{7}(x-21)[/tex]

[tex]y=-\dfrac{2}{7}(x)-\dfrac{2}{7}(-21)[/tex]

[tex]y=-\dfrac{2}{7}x+6[/tex]

Therefore, the equation of the required line is [tex]y=-\dfrac{2}{7}x+6[/tex].