If $a^2 + 49b^2 + c^2 + 18 = 2(28b - c - a)$ then the value of (a + 7b -c) is :

4

If $a^2 + 49b^2 + c^2 + 18 = 2(28b - c - a)$

then the value of (a + 7b -c) = ?

we can find the values of the variables by =

Coefficient of variables on right sides divide by coefficient of same variable on left side along with the signs as given below = 

So,

x = \(\frac{-2}{2}\) = -1

y = \(\frac{4}{7}\)

z = \(\frac{-2}{2}\) = -1

The value of (a + 7b – ​c) = [-1 + 7 × \(\frac{4}{7}\) – (-1)]

= (-1 + 4 + 1)

= (3 + 1) = 4