Solve the system by elimination method..?

Question

5x+5y=-11
7x-2y=13

Thank you :)

Answer 1

Elimination method Let 5x+5y = -11    _____________ (1)

7x-2y = 13     ______________  (2)

Apply multiplication property, multiple by 2 to (1) each side.

Apply multiplication property, multiple by 5 to (2) each side.

2(5x)+2(5y) = 2(-11)

5(7x)-5(2y) = 5(13)

⇒10x+10y = -22   ___________(3)

   35x-10y = 65     __________(4)

(3)+(4)⇒10x+10y = -22
             35x-10y = 65

__________________

            45x      = 43

               x = 43/45

Substitute the value of x in (1)

5(43/45)+5y = -11

Apply division property,divide by 5 to each side.

5/5(43/45)+5y/5 = -11/5

43/45+y = -11/5

Apply subtraction property, subtract 43/45 from to each sides.

43/45-43/45+y = -11/5-43/45

y = -11/5-43/45

y = -11(9)-43/45                                 (LCM of 5,45) = 45

y = -99-43/45

⇒y = -142/45

Solution x =43/45;y = -142/45