Solve 4x − 9 = 7

The solution of 4x − 9 = 7 is x = 4.

4x - 9 = 7\ \Rightarrow\ x = 4

Explain it step by step in chat Make a short video of it

The lines y = 4x − 9 and y = 7 meet at x = 4. 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.
$4x - 9 = 7$
2
Add 9 to both sides:
$4x - 9 + 9 = 7 + 9 \ \Rightarrow\ 4x = 16$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{16}{4} \ \Rightarrow\ x = 4$
4
Check: put x = 4 back into the equation.
$4\cdot4 - 9 = 16 - 9 = 7 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 9 = 7\ \Rightarrow\ x = 4 \]
\[ 4x - 9 = 7 \]
\[ 4x - 9 + 9 = 7 + 9 \ \Rightarrow\ 4x = 16 \]
\[ \frac{4x}{4} = \frac{16}{4} \ \Rightarrow\ x = 4 \]
\[ 4\cdot4 - 9 = 16 - 9 = 7 \checkmark \]

Trying values of x in 4x − 9 = 7

x	4x − 9	Equals 7?
2	-1	no
3	3	no
4	7	yes
5	11	no
6	15	no

Questions

What is x in 4x − 9 = 7?

The solution of 4x − 9 = 7 is x = 4.

How do you solve 4x − 9 = 7?

Add 9 to both sides to get 4x = 16, then divide both sides by 4 to get x = 4.

How do I check the answer?

Replace x by 4: 4(4) − 9 = 7, which is 7.

Solve 4x − 9 = 7

How to work it out

Trying values of x in 4x − 9 = 7

Questions

Similar equations