Question 32100
2A+4.2=3A-1.6 FIRST YOU NEED TO COMBINE THE UNKNOWN TERMS(A) AND ALSO COMBINE THE NUMBERS.
TO DO THIS YOU SUBTRACT (-2A) FROM BOTH SIDES OF THE EQUATION WHICH GIVES

2A-2A+4.2=3A-2A-1.6 NOW WE HAVE ELIMINATED THE A FROM THE LEFT SIDE OF THE EQUATION AND HAVE 4.2=A-1.6 NOW WE ADD 1.6 TO BOTH SIDES AND WE GET

4.2+1.6=A OR 5.8=A

PROOF SUBSTITUTE 5.8 FOR A IN THE ORIGINAL EQUATION WE HAVE
2(5.8)+4.2=3(5.8)-1.6 OR 11.6 +4.2=17.4-1.6 OR 15.8=15.8

REMEMBER YOU CAN DO ANYTHING (ADD, SUBTRACT, MULTIPLY, DIVIDE, RAISE TO A POWER OR TAKE THE ROOT OF ANY VALUE) AS LONG AS YOU PERFORM THIS OPERATIOPN TO BOTH SIDES OF THE EQUATION. IT'S A LOGICAL BALANCE BEAM THEREFORE YOU MUST CHANGE BOTH SIDES OF THE EQUATION IN ORDER TO NOT CHANGE THE BALANCE.