Question

3x + 4y = 7 and 2x + 3y = 5 by graphical method​

Answer 1

Elimination method:

3x + 4y = 7: multiply by 3

2x - 3y = 16: multiply by 4

9x + 12y = 21

8x - 12y = 64

Add the equations:

17x = 85

x = 5

3x + 4y = 7 => 3 * 5 + 4y = 7

4y = -8

y = -2

Answer 2

We are asked to solve 3x + 4y = 7 and 2x + 3y = 5 by graphical method.

~ Firstly let us consider

• 3x + 4y = 7 as equation 1

• 2x + 3y = 5 as equation 2

~ Now let us put x as 0 in equation 1

→ 3x + 4y = 7

→ 3(0) + 4y = 7

→ 0 + 4y = 7

→ y = 7/4

→ y = 1.8

• Henceforth, coordinates (0,1.8)

~ Now let us put y as 0 in equation 1

→ 3x + 4y = 7

→ 3x + 4(0) = 7

→ 3x + 0 = 7

→ 3x = 7

→ x = 7/3

→ x = 2.3

• Henceforth, coordinates (2.3,0)

~ Now let us put x as 0 in equation 2

→ 2x + 3y = 5

→ 2(0) + 3y = 5

→ 0 + 3y = 5

→ 3y = 5

→ y = 5/3

→ y = 1.6

• Henceforth, coordinates (0,1.6)

~ Now let us put y as 0 in equation 2

→ 2x + 3y = 5

→ 2x + 3(0) = 5

→ 2x + 0 = 5

→ 2x = 5

→ x = 5/2

→ x = 2.5

• Henceforth, coordinates (2.5,0) $\:$

They intersect at (1,1)