What was the mistake? *
бu — 4
бu — 7
-8u – 2
бu – 7
Step 1:
(6u — 4) - (-8u – 2)
бu – 7
Step 2:
бu — 8u — 4 — 2
бu – 7
Step 3:
-2u - 6
бu - 7