Solve 4x − 9 = 3

The solution of 4x − 9 = 3 is x = 3.

4x - 9 = 3\ \Rightarrow\ x = 3

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The lines y = 4x − 9 and y = 3 meet at x = 3. The solution of the equation is the x-coordinate of the point where the two sides are equal.

How to work it out

1
The goal is to get x alone. Undo the operations in the opposite order: first the subtraction, then the multiplication.
$4x - 9 = 3$
2
Add 9 to both sides:
$4x - 9 + 9 = 3 + 9 \ \Rightarrow\ 4x = 12$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{12}{4} \ \Rightarrow\ x = 3$
4
Check: put x = 3 back into the equation.
$4\cdot3 - 9 = 12 - 9 = 3 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 9 = 3\ \Rightarrow\ x = 3 \]
\[ 4x - 9 = 3 \]
\[ 4x - 9 + 9 = 3 + 9 \ \Rightarrow\ 4x = 12 \]
\[ \frac{4x}{4} = \frac{12}{4} \ \Rightarrow\ x = 3 \]
\[ 4\cdot3 - 9 = 12 - 9 = 3 \checkmark \]

Trying values of x in 4x − 9 = 3

x	4x − 9	Equals 3?
1	-5	no
2	-1	no
3	3	yes
4	7	no
5	11	no

Questions

What is x in 4x − 9 = 3?

The solution of 4x − 9 = 3 is x = 3.

How do you solve 4x − 9 = 3?

Add 9 to both sides to get 4x = 12, then divide both sides by 4 to get x = 3.

How do I check the answer?

Replace x by 3: 4(3) − 9 = 3, which is 3.

Solve 4x − 9 = 3

How to work it out

Trying values of x in 4x − 9 = 3

Questions

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