Hey there!
5(1 + 3x) = -115
5(1) + 5(3x) = -115
5 + 15x = -115
15x + 5 = -115
SUBTRACT 5 to BOTH SIDES
15x + 5 - 5 = -115 - 5
SIMPLIFY!
15x = -115 - 5
15x = -120
DIVIDE 15 to BOTH SIDES
15x/15 = -120/15
SIMPLIFY IT!
x = -120/15
x = -8
Therefore, the answer should be: x = -8
Good luck on your assignment & enjoy your day!
~Amphitrite1040:)