PLEASE HELP Rotate the given triangle 270°
counter-clockwise about the
origin.
2 21
-1 -1 3
-1
[1 1
?
[
-1
1
11

9514 1404 393

Step-by-step explanation:

The 270° CCW rotation is described by the transformation ...

  (x, y) ⇒ (y, -x)

That is, the first row of the transformed coordinate matrix is the same as the second row of the input matrix. The second row of the output matrix is the opposite of the first row of the input matrix.

5x + 3y = - 4

step-by-step explanation:

the equation of a line in standard form is

ax + by = c ( a is a positive integer and b, c are integers )

express the line first of all in slope- intercept form

y = mx + c ( m is the slope and c the y-intercept )

to calculate m use the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (7, - 3) and (x₂, y₂ ) = (4, - 8)

m = = -

y = - x + c ← is the partial equation

to find c substitute either of the 2 points into the partial equation

using (4, - 8 ), then

- 8 = - + c ⇒ c = -

y = - x - ← in slope-intercept form

multiply all terms by 3 to eliminate the fractions

3y = - 5x - 4 ( add 5x to both sides )

5x + 3y = - 4 ← in standard form