Simplifying
2.1x + -1(1 + 4.2x) = 5.3
2.1x + (1 * -1 + 4.2x * -1) = 5.3
2.1x + (-1 + -4.2x) = 5.3
Reorder the terms:
-1 + 2.1x + -4.2x = 5.3
Combine like terms: 2.1x + -4.2x = -2.1x
-1 + -2.1x = 5.3
Solving
-1 + -2.1x = 5.3
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '1' to each side of the equation.
-1 + 1 + -2.1x = 5.3 + 1
Combine like terms: -1 + 1 = 0
0 + -2.1x = 5.3 + 1
-2.1x = 5.3 + 1
Combine like terms: 5.3 + 1 = 6.3
-2.1x = 6.3
Divide each side by '-2.1'.
x = -3
Simplifying
x = -3
Hope i was helpful!