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Solution


Q.

While designing the school yearbook, a teacher asked a student to increase both the length and width of a particular photo by x units each in order to double the photo’s area. The original photo is 18 cm long and 12 cm wide.

Based on the above information, answer the following questions:

 

(iii) (b) Can any rational value of x make the new area equal to 220 cm²
1 210 cm²  
2 220 cm².  
3 215 cm².  
4 120 cm².  

Ans.

(2)

If new area is 220 cm², then: 216 + 30x + x² = 220 ⇒ x² + 30x - 4 = 0Using the quadratic formula:x=-30±302-4×1×-42×1=-30±900+162  = -30 ± √916/2    = -15 ± √229Clearly, x is not rationalHence, no rational value of x can make the new area equal to 220 cm².