Help me and please only answer it if you know it! NO LINKS!

Answer:
Step 1: Given --- 6 · 0 = 0
Step 2: Substitute. Any number plus its opposite is 0. --- 6(10+-10)=0
Step 3: Use the distributive property. --- 6·10+6·-10=0
Step 4: Multiply. --- 60+6·-10=0
Step 5: Subtract 60 from both sides. --- 6·-10=0-60
Step 6: Simplify to solve for 6·-10. --- 6·-10=-60