Question

if a + b is equal to 7ab is equal to 12 find a square + b square minus ab ​

Answer 1

Step-by-step explanation:

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Answer 2

$\sf{given \: } \\ \rm{a + b = 7} \\ \rm{ab = 12}$

$\rm{ {(a + b)}^{2} = {a}^{2} + {b}^{2} + 2ab} \\ \implies \rm{ {7}^{2} = {a}^{2} + {b}^{2} + 2(12)} \\ \implies \rm{ 49 = {a}^{2} + {b}^{2} + 24} \\ \implies\rm{{a}^{2} + {b}^{2} = 49 - 24} \\ \implies\rm{{a}^{2} + {b}^{2} = 25}$

$\rm{now}$

$\rm{ {a}^{2} + {b}^{2} - ab} = 25 - 12$

$\fbox{\rm{ {a}^{2} + {b}^{2} - ab = 13}}$