1.

In a `DeltaABC`, if a = 4, b = 3 and `angleA=60^(@)`, then c is a root of the equationA. `c^(2)-3c-7=0`B. `c^(2)+3c+7=0`C. `c^(2)-3c+7=0`D. `c^(2)+3c-7=0`

Answer» Correct Answer - A
We have,
`a=4, b=3 and A=60^(@)`
`therefore cosA=(b^(2)+c^(2)-a^(2))/(2bc)`
`impliescos60^(@)=(9+c^(2)-16)/(6c)impliesc^(2)-3c-7=0`


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