Question

-4x=30-2y , - 15 = - 2y + 11x Which the first step determining the given ordered pair solution?A. Replace x with 13 and y with - 1 in each equation B. Solve each equation for a variable C. Replace each variable in the first equation with -1 and each variable in the second equation with 13. D. Replace x with -1 and y with 13 in each equation. Is (-1,13) a solution of the system? Yes or no

Answer 1

B. Solve each equation for a variable

Is (-1,13) a solution of the system: Yes it is x =1, y= 13

Explanation:

-4x=30-2y

- 15 = - 2y + 11x

-4x=30-2y

-2y+4y = -30-------------------i

- 2y + 11x= - 15 ---------------ii

make x the subject of formula in equ i

-4x=30-2y

x= (30-2y)/-4

insert x= (30-2y)/-4 in equ ii

- 2y + 11x= - 15

-2y+ 11((30-2y)/-4)= -15

-2y+(330-22y)/4 = -15

-8y+330-22y/4 = -15

-8y-22y+330/4= -15

cross multiply

-30y+330 = 4x-15 = -60

-30y = -60-330

-30y =--390

y= -390/-30 = 13

if y = 13

x = (30-2y)/-4 = (30-2x13)/-4 = (30-26)/4 = 4/4 = 1

x=1 , y=13