The figure below shows a quadrilateral ABCD. Sides AB and DC are congruent and parallel: (image)

Which statement best describes a flaw in the student's proof?

Angle DBC and angle BDA form a pair of vertical angles, not a pair of alternate interior angles, which are congruent.

Triangles ABD and CDB are congruent by the SAS postulate instead of the SSS postulate.

Triangles ABD and BCD are congruent by the AAS postulate instead of the SSS postulate.

Angle DBC and angle BDA form a pair of corresponding angles, not a pair of alternate interior angles, which are congruent.

this is false ^.^ lol

answer:

a=9

step-by-step explanation: lmk if you need a explanation

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