Question

solve by elimination method: 3x-y=7; 2x+5y+1=0

Answer 1

Answer :

Here, the given equations are

3x - y = 7 ...(i)

2x + 5y = - 1 ...(ii)

Now, multiplying (i) by 5 and (ii) by (-1), we get

15x - 5y = 35

- 2x - 5y = 1

On subtraction, we get

17x = 34

⇒ x = 34/17

⇒ x = 2

Now, putting x = 2 in (i), we get

3 (2) - y = 7

⇒ 6 - y = 7

⇒ y = 6 - 7

⇒ y = - 1

Hence, the required solution be

x = 2 and y = - 1

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Answer 2

Answer:

x=2 and y= -1

Step-by-step explanation:

multiplying 1st equation with -5

-5(3x-y=7)  => -15+5y+35=0

on subtracting equation 2 from equation 1

(-15x-2x)+(5y-5y)+(35-1)  => which gives us  -17x+34=0

it means 34=17x

that means x= 34/17=2

x=2

on substituting value of x that is 2 in equation 1 (as your wish)

3*2-y=7

6-y=7

y=6-7

y=-1

so the answer is x=2 and y= -1