Solve 2x − 13 = −21

The solution of 2x − 13 = −21 is x = -4.

2x - 13 = -21\ \Rightarrow\ x = -4

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The lines y = 2x − 13 and y = -21 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.
$2x - 13 = -21$
2
Add 13 to both sides:
$2x - 13 + 13 = -21 + 13 \ \Rightarrow\ 2x = -8$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{-8}{2} \ \Rightarrow\ x = -4$
4
Check: put x = -4 back into the equation.
$2\cdot(-4) - 13 = -8 - 13 = -21 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 13 = -21\ \Rightarrow\ x = -4 \]
\[ 2x - 13 = -21 \]
\[ 2x - 13 + 13 = -21 + 13 \ \Rightarrow\ 2x = -8 \]
\[ \frac{2x}{2} = \frac{-8}{2} \ \Rightarrow\ x = -4 \]
\[ 2\cdot(-4) - 13 = -8 - 13 = -21 \checkmark \]

Trying values of x in 2x − 13 = −21

x	2x − 13	Equals -21?
-6	-25	no
-5	-23	no
-4	-21	yes
-3	-19	no
-2	-17	no

Questions

What is x in 2x − 13 = −21?

The solution of 2x − 13 = −21 is x = -4.

How do you solve 2x − 13 = −21?

Add 13 to both sides to get 2x = -8, then divide both sides by 2 to get x = -4.

How do I check the answer?

Replace x by -4: 2(-4) − 13 = -21, which is -21.

Solve 2x − 13 = −21

How to work it out

Trying values of x in 2x − 13 = −21

Questions

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