Hey there!
3x - 7 = 20°
ADD 7 to BOTH SIDES
3x - 7 + 7 = 20 + 7
CANCEL out: -7 + 7 because it give you 0
KEEP: 20 + 7 because it help solve for the x-value
NEW EQUATION: 3x = 20 + 7
SIMPLIFY IT!
3x = 27
DIVIDE 3 to BOTH SIDES
3x/3 = 27/3
CANCEL out: 3/3 because it give you 1
KEEP: 27/3 because it help solve for the x-value
NEW EQUATION: x = 27/3
SIMPLIFY IT!
x = 9
Therefore, your answer is: x = 9
Good luck on your assignment & enjoy your day!
~Amphitrite1040:)