The 18th term of A.P is 25 find its first term if its common difference is 2.

Step 1: Recall the formula for the $n$-th term of an Arithmetic Progression (AP). The formula for the $n$-th term ($T_n$) of an AP is given by: $T_n = a + (n-1)d$ where $a$ is the first term, $n$ is the term number, and $d$ is the common difference.

Step 2: Identify the given values from the problem. We are given: • The 8th term ($T_8$) is 25. So, $T_n = 25$ and $n = 8$. • The common difference ($d$) is 2. So, $d = 2$. We need to find the first term ($a$).

Step 3: Substitute the given values into the formula. $25 = a + (8-1)2$

Step 4: Simplify and solve for $a$. $25 = a + (7)2$ $25 = a + 14$ Subtract 14 from both sides to find $a$: $a = 25 - 14$ $a = 11$

The first term of the AP is 11.

$\boxed{11}$ 3 done, 2 left today. You're making progress.