HSA.CED.A.3 math practice. Learn by doing.

Let the integers be $n$, $n + 2$, and $n + 4$. Then $n + (n + 2) + (n + 4) = 75$, so $3n + 6 = 75$, $3n = 69$, and $n = 23$. The largest is $n + 4 = 27$.

Let the numbers be $k$, $2k$, and $4k$. Then $k + 2k + 4k = 63$, so $7k = 63$ and $k = 9$. The middle is $2k = 2(9) = 18$.

More than $2$ means $w > 2$. At most $10$ means $w \le 10$, so $2 < w \le 10$.

A minimum means $w$ must be at least that value, so use $\ge\textsf{.}$ Twice $n$ minus $12$ is $2n - 12\textsf{,}$ giving $w \ge 2n - 12\textsf{.}$

The system is $4b + 3f = 30$ and $2b + 5f = 22\textsf{.}$ Double the second equation: $4b + 10f = 44\textsf{.}$ Subtract the first: $7f = 14\textsf{,}$ so $f = 2\textsf{.}$

Lena is $2$ times as old as her brother, so $\ell = 2b$. The sum of their ages is $36$, so $\ell + b = 36\textsf{.}$

Let the integers be $n$, $n + 2$, and $n + 4$. Then $n + (n + 2) + (n + 4) = 84$, so $3n + 6 = 84$, $3n = 78$, and $n = 26$. The largest is $n + 4 = 30$.

Let the numbers be $3k$, $5k$, and $8k$. Then $3k + 5k + 8k = 96$, so $16k = 96$ and $k = 6$. The largest is $8k = 8(6) = 48$.