Equations ko Vidhi se Hal Karna

Class 7 Maths · Chapter 15: Anjaan ko Dhoondhna · NCERT Ganita Prakash section P2 7.2

Seekho

Trial and error chalta hai par dheema: 2n + 1 = 99 mein n = 30 (61, chhota), 50 (101, bada), 49 (99 ✓). Iski jagah ulte kram mein ulta karo. 4x − 7 = 21 mein x ko 4 se guna kiya, phir 7 ghataaya. Aakhri kadam pehle ulta: dono taraf 7 jodo, 4x = 28; phir dono taraf 4 se bhaag, x = 7. Jaancho: 4 × 7 − 7 = 21 ✓.

4x − 7 = 21 → 4x = 28 → x = 7

Dono taraf akshar: k + 8 = 12 − k. Dono taraf k jodo: 2k + 8 = 12; 8 ghataao: 2k = 4; to k = 2. Aur 7m = m − 3: m ghataao, 6m = −3, m = −1/2. Hal negative ya fraction bhi ho sakte hain.

k + 8 = 12 − k → k = 2

Bracket: −3(u + 2) = 2(u − 1) khulkar −3u − 6 = 2u − 2. 3u jodo: −6 = 5u − 2; 2 jodo: −4 = 5u, to u = −4/5. Aur agar 4k + 1 = 13, to k nikaale bina 8k + 2 = 2 × (4k + 1) = 26.

8k + 2 = 2(4k + 1) = 26

Shabd se equation: "Do numbers ka jod 76 aur ek doosre ka teen guna": x + 3x = 76, to x = 19 aur 57. "Meher ₹4000 se shuru karke har mahine ₹650 bachaati hai; Ishaan ₹5050 se shuru karke ₹500": 4000 + 650m = 5050 + 500m, to 150m = 1050 aur m = 7 mahine. Anjaan ka naam rakho, equation likho, hal karo, phir kahani mein jaancho.

x + 3x = 76 → x = 19

Explore: ek hi hal?

1. Har equation ko hal se sort karo.

Yaad rakho

• Kriyaaon ko ulte kram mein ulta karo, dono taraf ek jaisa.
• Akshar wale terms ek taraf, numbers doosri; jawaab hamesha jaancho.

Quick check

13 − z = 8 hal karo.

1. 5
2. 21
3. −5
4. −21

Socho

Kuch bachchon aur gadhon ke 28 sir aur 80 pair. Kitne-kitne?

Practice

Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.