Question

A line with an inclination of 45${}^{\circ }$ passes (-5/2, -9/2) what is the x-coordinate of a point on the line if its corresponding y-coordinate is 6?

• A. 6
• B. 7
• C. 8
• D. 9
• E. none of these

Answer 1

Answer: (C)

8

Let the equation of the line $y=mx+c$

The angle of inclination is ${45}^0$

and it passes through $(\frac{-5}{2},\frac{-9}{2})$

$\therefore m=tan{45}^0$

Thus,equation of line is $y=mx+c$

$\therefore \frac{-9}{2}-\frac{-5}{2}+c$

$=>-9=-5+2c$

$=>2c=-4$

$=>c=-2$

$\therefore$ equation of the line is $y=x-2$

For $y=6,x$ is ,

$6=x-2$

$=>x=8$