Question

7x-4y=18
4x+20y=27 solve e by elimination method

Answer 1

x=3

Explanation:

5(7x-4y=18)

4x+20y=27

35x-20y=90

4x+20y=27 just eliminate the -20 and +20 then get

39x=117

39x=117

then divide on both sides

Answer 2

x=2.14,y=0.75

Explanation:

7x-4y=18..(1)

4x+20y=27...(2)

Multiply (1) by 4

28x-16y=72...(3)

Multiply (2) by 7

28x+140y=189..(4)

Substrate (3) from (4)

156y=117

Divide both sides by 156

y=117/156

y=0.75

Substitute the value of y in (3)

28x-16(0.75)=72

28x-12=72

Add 12 to both sides

28x=60

Divide both sides by 28

x=2.14

Therefore x=2.14,y=0.75