Question

Anyone know the answer ?

Answer 1

n = -7 ∪ 7

=> n = |7|

Explanation:

S = 12cm = (n + 5) * (n + 5 - 10) / 2

`S = 12cm = ((n + 5) * (n + 5 - 10))/(2)\\\\=> 12 = ((n+5)(n-5))/(2) \\12 = (n^2-25)/(2) \\24 = n^2 - 25\\-n^2 = -25 - 24\\-n^2 = - 49\\n^2 = 49\\n = |7| =>\\ x_1 = -7\\x_2 = 7\\`

Answer 2

n = 7

Explanation:

`Area \: of \: \triangle = (1)/(2) * base * height \\ \\ 12 = (1)/(2) * (n + 5) * (n + 5 - 10) \\ \\ 12 * 2 = (n + 5)(n - 5) \\ \\ 24 = {n}^(2) - {5}^(2) \\ \\ 24 = {n}^(2) - 25 \\ \\ 24 + 25 = {n}^(2) \\ \\ {n}^(2) = 49 \\ \\ n = \pm \: √(49) \\ \\ n = \pm \: 7 \\ \\ n = - 7 \: \: or \: \: n = 7 \\`