it is given that the x intercept and y intercept of a straight line L are 3 and 5 respectively. If L passes through P(k, 10) find the value of k.​

Respuesta :

Answer:

k=-3

Step-by-step explanation:

Equation of a line

The general equation of a line can be written as:

Ax+By=C

The x-intercept is the point where the line crosses the x-axis, i.e. y=0, thus replacing x=3 and y=0:

A(3)+B(0)=C

3A=C

Solving for A:

A=C/3

The y-intercept is the point where the line crosses the y-axis, i.e. x=0, thus replacing x=0 and y=5:

A(0)+B(5)=C

5B=C

Solving for B:

B=C/5

Replacing into the general equation:

[tex]\displaystyle \frac{C}{3}x+\frac{C}{5}y=C[/tex]

Simplifying by C:

[tex]\displaystyle \frac{x}{3}+\frac{y}{5}=1[/tex]

The point P(k,10) belongs to the line, thus:

[tex]\displaystyle \frac{k}{3}+\frac{10}{5}=1[/tex]

Operating:

[tex]\displaystyle \frac{k}{3}+2=1[/tex]

[tex]\displaystyle \frac{k}{3}=-1[/tex]

Multiplying by 3:

[tex]\boxed{k=-3}[/tex]