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