Find the value c+d if c-d=2 and cd=63
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If you think by logic, c and d would come out to be 9 and 7, so c+d=16. But there is also a mathematical way to do this.
[tex]cd=63 c=63/d c-d=2 63/d - d=2 (63-d^{2})/d=2 d^{2}+2d-63=0 (d-7)(d+9)=0 so, d=7 or -9. so, c=9 or -7 so sum is 16 or -16. [/tex]
[tex]cd=63 c=63/d c-d=2 63/d - d=2 (63-d^{2})/d=2 d^{2}+2d-63=0 (d-7)(d+9)=0 so, d=7 or -9. so, c=9 or -7 so sum is 16 or -16. [/tex]
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