Respuesta :

7.

The required equation of the line is y= 2x-5

8.

y=30

Step-by-step explanation:

Given , a line passes through the points (1,-3) and (3,1)

The equation of line which passes through the points [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex] is

[tex]y - y_1=\frac{y_2-y_1}{x_2-x_1} (x-x_1)[/tex]

Here [tex]x_1 = 1 , y_1= -3[/tex]     and      [tex]x_2 = 3 , y_2= 1[/tex]

The required equation of the line is

[tex]y+3=\frac{1+3}{3-1} (x-1)[/tex]

[tex]\Leftrightarrow y +3 =2(x-1)[/tex]

[tex]\Leftrightarrow y =2x-2-3[/tex]

[tex]\Leftrightarrow y =2x-5[/tex]

8.

Given, y varies directly with x and y=24 when x=8

Therefore,

[tex]y\propto x[/tex]

[tex]\Rightarrow y = kx[/tex].........(1)

y = 24 when x=8

[tex]\therefore 24 = 8k[/tex]

[tex]\Rightarrow k =3[/tex]

Equation (1) becomes

y= 3x

So, when x=10

y=3×10

⇒y=30