8=4x-6x
8= -2x
8/-2= -2x/-2
X=-4
First step:Combine like terms so subtract 4x-6x= -2x so you will get 8=-2x
Note: You combine it because there both x and there in the same equal sign position.
Second step: Get x by it self by dividing -2 on each side as shown above.You divide it because you do the opposite of multiplying.
Answer x=-4
Sorry Idk where the equal sign is I am skipping the second problem.
-21-2b= -3(2b-1)
-21-2b= -6b+3
+2b +2b
-21= -4b+3
-3 -3
-24= -4b
-24/-4= -4b/-4
6=b or b=6
I hope I helped sorry I didn't explain this problem step by step like the 1 st one.