Question

use the method of substitution to solve each other of the pair of simultaneous equations 2x-9y =9, 5x +2y =27​

Answer 1

$\sf\huge\bold{\underline{\underline{{Solution}}}}$

We have given two Equations :2x-9y=9 & 5x+2y=27

How to solve ?

step 1:from given two Equations we convert any Equation in the form of x or y .

Step 2: Put step 1 into other Equation and hence evaluate it we will find any Variable.

Step 3: put step 3 into step 1 We will find another Variable.

➙2x-9y=9

➙x= (9+9y)/2----(1)

➙5x+2y= 27

From equation 1

➙5(9+9y)/2+2y= 27

➙45+45y/2+2y=27

➙45+45y+4y/2=27

➙45+45y+4y=54

➙45+49y= 54

➙49y= 54-45

➙49y= 9

➙y= 9/49---(2)

From equation 2

➙x= (9+9y)÷2

➙x=9+9(9/49)÷2

➙x=(9+81/49)÷2

➙x=(441+81/49)÷2

➙x=522/49×1/2

➙x=261/49

Check:

➙5x+2y=27

Taking LHS

➙5(261/49)+2(9/49)

➙1305/49+18/49

➙1323/49

= 27

Since LHS = RHS(Verified)

Answer 2

We have given two Equations :2x-9y=9 & 5x+2y=27

How to solve ?

step 1:from given two Equations we convert any Equation in the form of x or y .

Step 2: Put step 1 into other Equation and hence evaluate it we will find any Variable.

Step 3: put step 3 into step 1 We will find another Variable.

➙2x-9y=9

➙x= (9+9y)/2----(1)

➙5x+2y= 27

From equation 1

➙5(9+9y)/2+2y= 27

➙45+45y/2+2y=27

➙45+45y+4y/2=27

➙45+45y+4y=54

➙45+49y= 54

➙49y= 54-45

➙49y= 9

➙y= 9/49---(2)

From equation 2

➙x= (9+9y)÷2

➙x=9+9(9/49)÷2

➙x=(9+81/49)÷2

➙x=(441+81/49)÷2

➙x=522/49×1/2

➙x=261/49

Check:

➙5x+2y=27

Taking LHS

➙5(261/49)+2(9/49)

➙1305/49+18/49

➙1323/49

= 27

Since LHS = RHS(Verified)