Answer:

Step-by-step explanation:
-5+2(10b-2)=31
Expand brackets.
-5+20b-4=31
-9+20b=31
Add 9 on both sides.
20b=40
Divide both sides by 20
b=2
Answer:
10000
Step-by-step explanation:
Answer:
See below
Step-by-step explanation:
x(x-2y)-(y-x)2
Final result :
-y2
Step by step solution :
Step 1 :
Equation at the end of step 1 :
x • (x - 2y) - (y - x)2
Step 2 :
2.1 Evaluate : (y-x)2 = y2-2xy+x2
Final result :
-y2