Question

Calculati media aritmetica a numerelor reale a si b, daca:
a)a=1,25:0,05-2√7*(-2,5-4,8),
b=5√7*(-2,4)+6,24:(0,04-0,24);

Answer 1

$\displaystyle a=1,25:0,05-2 \sqrt{7} \cdot (-2,5-4,8) \\ a=25-2 \sqrt{7} \cdot (-7,3) \\ a=25+14,6 \sqrt{7} \\ b=5 \sqrt{7} \cdot (-2,4)+6,24:(0,04-0,24) \\ b=-12 \sqrt{7} +6,24:(-0,2) \\ b=-12 \sqrt{7} -31,2 \\ m_a= \frac{a+b}{2} = \frac{25+14,6 \sqrt{7} -12 \sqrt{7} -31,2}{2} = \frac{2,6 \sqrt{7} -6,2}{2} = \\ \\ = \frac{\not 2(1,3 \sqrt{7} -3,1)}{\not2} =\boxed{1,3 \sqrt{7} -3,1}$