X+y=13 and 5x-8y=0 Plz help!!!?

Question

1.1) Solve for x and y simultaneously

1.2) Find the ratio x over y

1.3) Write the ratio x over y in the form of decimal  

Answer 1

Elimination method

1.1) Given equations x+y =13 ---> (1)

5x-8y = 0 ---> (2)

Multiple to each side of equation by negitive 5.

-5x-5y = -65 ----> (3)

To eliminate the x value add the equations (3)&(2).

-5x-5y = -65

5x-8y = 0

___________

-13y = -65

Dvide to each side by negitive 13.

-13y/-13 = -65/-13

⇒y = 5

Substitute the y value in (1).

x+5 = 13

Subtract 5 from each side.

x+5-5 = 13-5

⇒x = 8

Solution x = 8, y = 5.

1.2) Ratio over x over y is  8/5

1.3) Ratio over x over y in the form of decimal is 1.6.