Solve 4x − 9 = 43

The solution of 4x − 9 = 43 is x = 13.

4x - 9 = 43\ \Rightarrow\ x = 13

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The lines y = 4x − 9 and y = 43 meet at x = 13. 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.
$4x - 9 = 43$
2
Add 9 to both sides:
$4x - 9 + 9 = 43 + 9 \ \Rightarrow\ 4x = 52$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{52}{4} \ \Rightarrow\ x = 13$
4
Check: put x = 13 back into the equation.
$4\cdot13 - 9 = 52 - 9 = 43 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 9 = 43\ \Rightarrow\ x = 13 \]
\[ 4x - 9 = 43 \]
\[ 4x - 9 + 9 = 43 + 9 \ \Rightarrow\ 4x = 52 \]
\[ \frac{4x}{4} = \frac{52}{4} \ \Rightarrow\ x = 13 \]
\[ 4\cdot13 - 9 = 52 - 9 = 43 \checkmark \]

Trying values of x in 4x − 9 = 43

x	4x − 9	Equals 43?
11	35	no
12	39	no
13	43	yes
14	47	no
15	51	no

Questions

What is x in 4x − 9 = 43?

The solution of 4x − 9 = 43 is x = 13.

How do you solve 4x − 9 = 43?

Add 9 to both sides to get 4x = 52, then divide both sides by 4 to get x = 13.

How do I check the answer?

Replace x by 13: 4(13) − 9 = 43, which is 43.

Solve 4x − 9 = 43

How to work it out

Trying values of x in 4x − 9 = 43

Questions

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