4. If angle A and anlge B are both supplementary to Angle C and angle A is 70°, Find angle B. Sketch a picture or use an equation to explain your answer.

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

2.14x - 12.18 = -5.76

add 12.18 to each side

2.14x -12.18 +12.18 = -5.76 +12.18

2.14 x =6.42

divide by 2.14

2.14x/2.14 = 6.42/2.14

x=3

the one where 1 and 2 are directly across from each other.  

see image