contestada

the graph of a line in the xy-plane slope 1/3 and contains the point (9,1). the graph of a second line passes through the points (-2,4) and (5,-3). if the two lines intersect at (a,b), what is the value of a+b?

Respuesta :

Answer:

[tex]a + b = 2[/tex]

Explanation:

The equations are determined by the definition of line equation:

First line

[tex]1 = \frac{1}{3}\cdot (9) + b[/tex] (Line equation)

[tex]1 = 3 + b[/tex]

[tex]b = -2[/tex] (x-Intercept)

The equation of the first line is:

[tex]y = \frac{1}{3}\cdot x - 2[/tex]

Second line

[tex]m = \frac{(-3)-4}{5-(-2)}[/tex]

[tex]m = - 1[/tex] (Slope)

[tex]-3 = -1 \cdot (5)+b[/tex]

[tex]-3 = -5 + b[/tex]

[tex]b = 2[/tex] (x-Intercept)

The equation of the second line is:

[tex]y = -x + 2[/tex]

First, y is eliminated by equalization and x is found:

[tex]\frac{1}{3}\cdot x -2 = -x +2[/tex]

[tex]\frac{4}{3}\cdot x = 4[/tex]

[tex]x = 3[/tex] (a)

Now, y is finally determined by direct substitution:

[tex]y = -3+2[/tex]

[tex]y = -1[/tex] (b)

The value of a + b is:

[tex]a + b = 2[/tex]