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Let `S={x in R: x ge 0 and 2|(sqrt(x)-3|+sqrt(x)(sqrt(x)-6)+6=0}` then S (1) is an empty set (2) contains exactly one element (3) contains exact;y two elements (4) contains exactly four elementsA. contains exactly four elementsB. is an empty setC. contains exactly one elementD. contains exactly two elements |
Answer» Correct Answer - 4 Given equation is `2 |sqrt(x) - 3|+ x - 6 sqrt(x)+6= 0 ` or ` 2 |sqrt(x) - 3|+ (sqrt(x) - 3)^(2) - 3 = 0 ` Let `|sqrt(x) - 3| = y` ` therefore y^(2) + 2y - 3 = 0 ` `rArr (y - 1) (y + 3) = 0 ` ` rArr y = 1, - 3 ` `therefore |sqrt(x) - 3| =1` `rArr sqrt(x) - 3 = pm 1` `rArr sqrt(x) = 2, 4` `rArr x = 4, 16 ` So, equation has two solutions. |
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