Question

Consider the equations 15x + 9y = 45 and 9x + 8y = 12. Solve the system of equations using elimination. Give your solution to the system as a pair of coordinates.

Answer 1

(-5.77, 6.46)

Explanation:

15x + 9y = 45 ----------- i

9x + 8y = 12----------------ii

Multiply equation i by 9 the coefficient of x in equ ii

And equation ii by 15 the coefficient of x in equ I

9 x 15x + 9y = 45 ----------- i

15 x 9x + 8y = 12----------------ii

135x+81y = 405

135x+120y= 180

Subtract equation ii from I

135x-135x+81y-(+120y)= 405-180

-39y=225

y = 225/-39 = -5.77

Insert the value of y in equ i

15x + 9y = 45

15x+9(-5.77) = 45

15x-51.92=45

15x = 45+51.92

15x= 96.92

x = 96.92/15= 6.46

(x,y) = (-5.77, 6.46)

x = 6.92/15