6785∆4 is a 6-digit number with one of its digit represented by ∆. What can be the value of ∆ if 6785∆4 is divisible by 9

The value of the missing digit is 6.

Step-by-step explanation:

When a number is divisible by 9, the sum of the digits must be 9 or a multiple of 9.

Given digits = 6785∆4

the sum of the digits = 30 + ∆

30 + ∆ = 36

∆ = 36 - 30

∆ = 6

Thus, the value of the missing digit is 6.

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a