Question

solve each equation system by the addition method 3x+4y=7 2x+y=3

Answer 1

3x+4y=7
2x+y=3<- multiply by 4

Answer 2

that is 8x + 4y = 12

Answer 3

8x + 4y = 12
3x + 4y = 7

Answer 4

add them
while adding the sign in the equation below changes

Answer 5

i.e 3x becames -3s
4y become -4y and 7 becomes -7
This was the equation we added

Answer 6

so now
9x + 4y = 12
-3x - 4y = -7
agree?

Answer 7

4y gets canceled

Answer 8

OMG! OTS 8X AND NOT 9X SORRY MY BAD!

Answer 9

so now
8x + 4y = 12
-3x - 4y = -7 agree?

Answer 10

thats 5x = 5

Answer 11

divide both sides by 5

Answer 12

that gives x =1

Answer 13

put x = 1 in 3x + 4y = 7 to get the value of y

Answer 14

3(1) + 4y = 7
3 + 4y = 7
4y = 4

Answer 15

divide both sides by 4

Answer 16

y = 1

Answer 17

therefore ordered pair is
(1,1)

Answer 18

this is correct but to keep things simple
remember the objective is to eliminate one of the variable when you add the equations
for this you would multiply by -4 so that the y's cancel
less chances of error when trying to switch signs and without explanation