SOLUTION: 5x + 4y = 22, 3x + 5y =21 using substitution method and 3x + 2y =10, x + 2y =7 using elimination method

Question 704042: 5x + 4y = 22, 3x + 5y =21 using substitution method and 3x + 2y =10, x + 2y =7 using elimination method
Answer by sachi(548) (Show Source): You can put this solution on YOUR website!
using substitution method
5x + 4y = 22.....A
3x + 5y =21 ....B
from A
5x = 22- 4y
or x=(22- 4y)/5....C
substituting the value of x from C in B
3(22- 4y)/5 + 5y =21
or 3(22- 4y) + 25y =105 multiplying both sides by 5
or 66-12y+25y=105
or 13y=105-66=39
or y=39/13=3
from C
x=(22-12)/5=2
so x=2 & y=3
using elimination method
3x + 2y =10......D
x + 2y =7 .......E
multiplying both sides of E by 3
3x + 6y =21........F
3x + 2y =10........D
- - -
---------------------
4y=11
or y=11/4
from E
x+2*11/4=7
or x=7-11/2=3/2
so x=3/2& y=11/4
ans

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