What is the numerical value of the second term in the following seq

What is the numerical value of the second term in the following sequence: \(x, x+1, x+3, x+6, x+10, x+15\)…? (1) The sum of the first and second terms is one-half the sum of the third and fourth terms. (2) The sum of the sixth and seventh terms is 43. Source: Master (…)