Solve 4x − 9 = 47

The solution of 4x − 9 = 47 is x = 14.

4x - 9 = 47\ \Rightarrow\ x = 14

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The lines y = 4x − 9 and y = 47 meet at x = 14. 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.
$4x - 9 = 47$
2
Add 9 to both sides:
$4x - 9 + 9 = 47 + 9 \ \Rightarrow\ 4x = 56$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{56}{4} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$4\cdot14 - 9 = 56 - 9 = 47 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 9 = 47\ \Rightarrow\ x = 14 \]
\[ 4x - 9 = 47 \]
\[ 4x - 9 + 9 = 47 + 9 \ \Rightarrow\ 4x = 56 \]
\[ \frac{4x}{4} = \frac{56}{4} \ \Rightarrow\ x = 14 \]
\[ 4\cdot14 - 9 = 56 - 9 = 47 \checkmark \]

Trying values of x in 4x − 9 = 47

x	4x − 9	Equals 47?
12	39	no
13	43	no
14	47	yes
15	51	no
16	55	no

Questions

What is x in 4x − 9 = 47?

The solution of 4x − 9 = 47 is x = 14.

How do you solve 4x − 9 = 47?

Add 9 to both sides to get 4x = 56, then divide both sides by 4 to get x = 14.

How do I check the answer?

Replace x by 14: 4(14) − 9 = 47, which is 47.

Solve 4x − 9 = 47

How to work it out

Trying values of x in 4x − 9 = 47

Questions

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