algebra 1 homework help

Question

Find the intersection point for 3y + 5x = 20 and 5y + 3x = 20?

Answer 1

3y+5x = 20_______ (1)

5y+3x = 20 _______(2)

(!)*5 - (2)*3

15y+25x = 100

15y+9x  = 60

(-)    (-)     (-)

____________

      16x = 40 

Apply division property, divide by 16 to each side.

     16x/16 = 40/16

          x = 40/16

          x = 5/2

x = 5/2 in (1)

3y + 5(5/2) = 20

3y + 25/2 = 20

Apply subtraction property,subtract 25/2 from each side.

3y+25/2-25/2 = 20 - 25/2

3y = 20-25/2

3y = (40-25)/2

3y = 15/2

Apply division property, divide by 3 to each side.

3y/3 = 15/6

y = 15/6

y = 5/2

check

3*5/2 + 5*5/2 = 20

15/2 + 25/2 = 20

40/2 = 20

20 = 20

x, y values are coordinate pair of intersection point.

So the intersection point to given lines is (5/2,5/2)