Question

Q=> Solve the following pair of linear equations by the substitution and cross-multiplication methods:
8x + 5y = 9
3x + 2y = 4​

Answer 1

HERE IS YOUR ANSWER MATE.....;

8x + 5y = 9 …………………..(1)

3x + 2y = 4 ……………….….(2)

From equation (2) we get;

x = (4 – 2y) / 3 ……………………. (3)

Substituting this value in equation 1, we get

8[(4 – 2y)/3] + 5y = 9

32 – 16y + 15y = 27

-y = -5

y = 5 ……………………………….(4)

Substituting this value in equation (2), we get

3x + 10 = 4

3x = -6

x = -2

Thus, x = -2 and y = 5.

Now, Using Cross Multiplication method:

8x +5y – 9 = 0

3x + 2y – 4 = 0

x/(-20 + 18) = y/(-27 + 32 ) = 1/(16 – 15)

-x/2 = y/5 = 1/1

∴ x = -2 and y =5

Hope it's Helpful.....:)