{(6 x+7 y=6,12 x-21 y=5) substitution method

Question

i have to find the x,y of this using the substituion method and im completley lost i dont know how todo it .

Answer 1

6x+7y=6, so 12x+14y=12
12x-21y=5
The second equation can be written: 12x=5+21y which can be substituted in the other equation in place of 12x.
5+21y+14y=12, so 35y=7, and y=7/35=1/5.
Substitute this value of y in 6x+7y=6: 6x+7/5=6. Multiply through by 5:
30x+7=30, so 30x=23 and x=23/30. Check the correctness by substituting x and y in the other original equation:
12*23/30-21/5=2*23/5-21/5=(46-21)/5=25/5=5. Correct!
So the confirmed answer is x=23/30, y=1/5.