a = ?
4a + 12 = 7a - 9
please show workings
4a + 12 = 7a - 9
add 9 to both sides
4a + 12 + 9= 7a - 9 + 9
4a + 21 = 7a
subtract 4a from each side
4a + 21 - 4a= 7a - 4a
21 = 3a
divide each side by 3
21/3 = 3a/3
7 = a
or a = 7
To find the value of 'a' in the equation 4a + 12 = 7a - 9, we can follow these steps:
Step 1: Simplify the equation by combining like terms on both sides.
On the left side of the equation, we have 4a + 12.
On the right side of the equation, we have 7a - 9.
Combining like terms, the equation becomes:
12 = 3a - 9.
Step 2: Isolate the variable 'a' on one side of the equation by moving the constant term to the other side.
To do this, add 9 to both sides of the equation. This gives us:
12 + 9 = 3a,
which simplifies to:
21 = 3a.
Step 3: Solve for 'a' by dividing both sides of the equation by 3.
Dividing both sides by 3 gives us:
21/3 = a,
which simplifies to:
7 = a.
Therefore, the value of 'a' is 7.