Next time, ask us before you develop a headache. We want healthy students.
(7k3-7) - (2+3k3)
This only looks complicated.
Everything is subtraction and addition.
Let's eliminate the parentheses...
Please note the fact that because both figures in the second parenthetical equation are being subtracted, these are each converted from positive into negative. If these parenthetical figures are negative, these would be converted from negative into positive. If, in the second parenthetical equation, we are adding rather than subtracting positive figures, these would remain positive. If we are adding negative figures, these would remain negative.
Let's combine like terms...