Question

Anyone know the answer ?

Answer 1

Answer:

n = -7 ∪ 7

=> n = |7|

Step-by-step explanation:

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

$S = 12cm = \frac{(n + 5) * (n + 5 - 10)}{2}\\\\=> 12 = \frac{(n+5)(n-5)}{2} \\12 = \frac{n^2-25}{2} \\24 = n^2 - 25\\-n^2 = -25 - 24\\-n^2 = - 49\\n^2 = 49\\n = |7| =>\\ x_1 = -7\\x_2 = 7$

Answer 2

Answer:

n = 7

Step-by-step explanation:

$Area \: of \: \triangle = \frac{1}{2} \times base \times height \\ \\ 12 = \frac{1}{2} \times (n + 5) \times (n + 5 - 10) \\ \\ 12 \times 2 = (n + 5)(n - 5) \\ \\ 24 = {n}^{2} - {5}^{2} \\ \\ 24 = {n}^{2} - 25 \\ \\ 24 + 25 = {n}^{2} \\ \\ {n}^{2} = 49 \\ \\ n = \pm \: \sqrt{49} \\ \\ n = \pm \: 7 \\ \\ n = - 7 \: \: or \: \: n = 7$