someone please help me!!!!!!!

Step-by-step explanation:
In the second step while opening the bracket, instead of 'a', there should be - 4a.
Answer:
From Step 2 every step is wrong
Step-by-step explanation:
Ste p 1 : 3a - 5b = 12 - 4(b + a)
Step 2 : 3a - 5b = 12 - 4b - 4a [ Last term instead - 4a she\he wrote + a ]
Step 3 : 7a - 5b = 12 - 4b
Step 4 : 7a = 12 + b
[tex]Step 5 : a = \frac{12 + b}{7}[/tex]