5abcd is a quadrilateral. ao and bo are the angle bisectors of a
and b which meet at o. if c = 70°, d=50°, find aob

60°

Step-by-step explanation:

sum of interior angles of quadrilateral is 360°

∠C = 70°

∠D = 50°

∠C + ∠D = 120°

∴ ∠A + ∠B = 360° - 120° =240°

AO and BO bisect ∠A and ∠B

∠OAB + ∠OBA = 1/2 x ( ∠A + ∠B) = 120°

∠AOB = 180° - (∠OAB + ∠OBA) = 180° - 120° = 60°

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