Question

How do you solve the following system of equations algebraically: 3x + 2y = 4, 4x + 3y = 7?

Answer 1

Hiiii. Hope the solution will help you :)

See,

We have 4 methods to solve the

given system of equations......

1.Graphically

2. Substitution

3.Elimination

4. Cross multiplication

Here I am using the 3rd one.

In this method,

The coefficient of x of equation 1 is multiplied with the second equation and vise versa.... And then both the new equations are subtracted.......

3x+2y=4

Multiplying 4 both the sides,

4* (3x+2y)=4*4

12x+8y=16.......(i)

Now,

4x+3y=7

Multiplying &3 both the sides,

3*(4x+3y) =3*7

12x+9y=21......(ii)

(ii)-(i)

12x+9y - (12x +8y)=21-16

12x+9y-12x-8y=5

y=5

So,

As 3x+2y=4 emplies that

3x +2*5=4

3x+10=4

3x=4-10

3x=-6

x=(-6/3)=(-2)