Solve 11x − 15 = 40

The solution of 11x − 15 = 40 is x = 5.

11x - 15 = 40\ \Rightarrow\ x = 5

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The lines y = 11x − 15 and y = 40 meet at x = 5. 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.
$11x - 15 = 40$
2
Add 15 to both sides:
$11x - 15 + 15 = 40 + 15 \ \Rightarrow\ 11x = 55$
3
Divide both sides by 11:
$\frac{11x}{11} = \frac{55}{11} \ \Rightarrow\ x = 5$
4
Check: put x = 5 back into the equation.
$11\cdot5 - 15 = 55 - 15 = 40 \checkmark$

LaTeX source of the formulas on this page

\[ 11x - 15 = 40\ \Rightarrow\ x = 5 \]
\[ 11x - 15 = 40 \]
\[ 11x - 15 + 15 = 40 + 15 \ \Rightarrow\ 11x = 55 \]
\[ \frac{11x}{11} = \frac{55}{11} \ \Rightarrow\ x = 5 \]
\[ 11\cdot5 - 15 = 55 - 15 = 40 \checkmark \]

Trying values of x in 11x − 15 = 40

x	11x − 15	Equals 40?
3	18	no
4	29	no
5	40	yes
6	51	no
7	62	no

Questions

What is x in 11x − 15 = 40?

The solution of 11x − 15 = 40 is x = 5.

How do you solve 11x − 15 = 40?

Add 15 to both sides to get 11x = 55, then divide both sides by 11 to get x = 5.

How do I check the answer?

Replace x by 5: 11(5) − 15 = 40, which is 40.

Solve 11x − 15 = 40

How to work it out

Trying values of x in 11x − 15 = 40

Questions

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