Anonymous
Anonymous asked in Science & MathematicsMathematics · 2 months ago

# Quick question on math?

Write a linear system that has a point of intersection of (2,-4).

(1)

(2)

Relevance
• 2 months ago

y = mx + b

Pick an arbitrary value of m:

m = 1

y = x + b

Plug in x=2, y=-4

-4 = 2 + b

b = -4 - 2

b = -6

y = x - 6

Now pick a different arbitrary slope:

m = 2

y = 2x + b

Plug in the point again:

-4 = 2(2) + b

-4 = 4 + b

b = -4 - 4

b = -8

y = 2x - 8

You could pick any 2 different values of m and make this work.

Answer (one of infinitely many possibilities):

[1] y = x - 6

[2] y = 2x - 8

• ?
Lv 7
2 months ago

My solution is

y=-4

y=3x-10

• ?
Lv 6
2 months ago

You can have any slope you want. So pick the slope, and solve for the y-intercept that puts (2, -4) on the line.

1) Let slope be, say, 6

y = 6x + b

-4 = 6(2) + b

b = -16

y = 6x - 16 is one line.

2) Let slope be -3

y = -3x + b

-4 = -3(2) + b

b = 2

y = -3x + 2 is another line.

• Anonymous
2 months ago

The equation of any straight line through the point (X.Y) is;

y- Y = m(x-X)

X=2 and Y=-4  and you can pick *any* 2 values of m. E.g.

m=1 gives y-(-4) = 1(x-2 )

y = x - 6

m=2 gives  y-(-4) = 2(x-2 )

y =  2x - 8

• 2 months ago

The simplest way:

(1) x = 2

(2) y = -4

• ?
Lv 7
2 months ago

The equation of a line y₁ passing through (2,-4) with slope 4 is

y₁ -  -4 = 4(x - 2)

y₁ = 4x - 12

The equation of a line y₂ passing through (2, -4) with slope -¾ is

y₂ -  -4 = -¾(x - 2)          y₂ = -¾x - ⁵⁄₂

A system of linear equatinons that has a point of intersection of (-2,4) is

(1) y₁ = 4x - 12   .....................ANS

(2) y₂ = -¾x - ⁵⁄₂                      .ANS

• 2 months ago

y = -2 x

y = x - 6

• 2 months ago

You can set up two general linear equations based on this form:

y = mx + b

Where x = 2 and y = -4 in both with different slopes (m).  I'll use m = -1 and m = 2.  That gives us:

-4 = -1(2) + b and -4 = 2(2) + b

-4 = -2 + b and -4 = 4 + b

-2 = b and -8 = b

Now that we have two b's complete the equations:

y = -x - 2 and y = 2x - 8

That is one of many systems of equations that will have the point (2, -4) as a solution.