Question

Hallar la ecuación de la recta que pasa por el punto P(-3,-1) y por el punto de intersección de las rectas 2x − y = 9 y 3x − 7y = 19

Answer 1

Answer:

y = -1

Step-by-step explanation:

The standard form of equation of a line is y = mx+b

m is the slope

b is the y intercept

Get the coordinate of the point of interception of the line 2x - y = 9 and 3x - 7y = 19

Make y the subject of the formula in both expressions

For 2x  - y = 9

- y = 9- 2x

y = 2x - 9

Similarly for 3x - 7y = 19

-7y = 19 - 3x

7y = 3x - 19

y = 3/7 x - 19/7

Equating both expressions

2x - 9 = 3/7 x - 19/7

Multiply through ny 7

14x - 63 = 3x - 19

14x - 3x = -19 + 63

11x = 44

x = 44/11

x = 4

Since y =2x - 9

y = 2(4) - 9

y = 8-9

y = -1

Hence the coordinate of intersection is at (4, -1)

Get the equation of the line passing through (-3, -1) and (4, -1)

Slope m = -1+1/4+3

m = 0/7

m = 0

Get the intercept

Substitute m = 0 and (-3, -1) into y = mx+b

-1 = 0(-3) + b

-1 = b

b = -1

Get the required equation

Recall that y = mx + b

y = 0x + (-1)

y = -1

Hence the required equation is y = -1