Which ordered pair is the solution to the system of equations?
2x-5y=-5
x+2y=11
  A.(3, 4)  B.(5, 3)  C.(7, 2)  D.(15, 7)


Sagot :


You asked a question similar to this recently. This time I will show the multiplication and subtraction method instead of the substitution one.

2x-5y=-5 | x+2y=11

2x-5y=-5 | 2x+4y=22

Subtract the first equation form the second.

9y=27

y=3

Then substitute.

x+2(3)=11

x+6=11

x=5

The final answer is the ordered pair (5,3).

Im using the substitution method because i feel that its easier but you can use any method you prefer. You would start with one equation and isolate a variable( leave it by itself). I started with the second equation (x+2y=11) because the variable x does not have a coeficcient (the number before the variable). I just subtracted 2y from both sides of the equation and got x=-2y+11 or x=11-2y (same thing). Then i substituted or plugged in -2y+11 as x in the firth equation so it would be 2(-2y+11)-5y=-5 . Then i would distribute to get -4y+22-5y=-5 and combine like terms to solve and get that y=3. Then just plug in 3 as y in the second equation and solve for x to get that x=5 and y=3 making your ordered pairs (5,3). Ps sorry if it was long hope i helped