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