Question

найдите значение выражения (b+5)^2 - b^2 - 5 при b = 9/10

Answer 1

$\displaystyle\bf\\(b+5)^{2}-b^{2} -5=b^{2} +10b+25-b^{2}-5=10b+20\\\\\\b=\frac{9}{10} \\\\\\10b+20=10\cdot \frac{9}{10} +20=9+20=29\\\\\\Otvet \ : \ 29$