Question

Solve each system by substitution

|2x+3y=0
|x+2y=-1

————————————

|1/2x+1/3y=5
|1/4x+y=10





Pls show step by step

Answer 1

Explanation:

Q70.

2x+3y = 0 ---(1)

x+2y = -1 ---(2)

from (1) :

3y = -2x

`y =- (2)/(3) x ---(3)`

sub (3) into (2) :

`x+2(-(2)/(3) x) = -1 \\\\-(1)/(3) x = -1 \\ \\x = 3 ---(4)`

sub (4) into (1) :

2(3)+3y = 0

3y = -6

y = -2

therefore, x = 3 and y = -2.

Q72.

`(1)/(2) x +(1)/(3)y = 5 ---(1) \\ \\ (1)/(4)x+y = 10 ---(2)`

from (1) :

3x+2y = 30

2y = 3x+30

`y = (3x+30)/(2) ---(3)`

from (2) :

x+4y = 40 ---(4)

sub (3) into (4) :

`x+4((3x+30)/(2)) = 40 \\ \\x+6x+60 = 40 \\\\7x = 20\\\\x = -(20)/(7) ---(5)`

sub (5) into (4) :

`(-(20)/(7))+4y= 40 \\ \\4y = (300)/(7)\\ \\y = (75)/(7)`