Solve 3x + 4 = −5

The solution of 3x + 4 = −5 is x = -3.

3x + 4 = -5\ \Rightarrow\ x = -3

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The lines y = 3x + 4 and y = -5 meet at x = -3. 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 addition, then the multiplication.
$3x + 4 = -5$
2
Subtract 4 from both sides:
$3x + 4 - 4 = -5 - 4 \ \Rightarrow\ 3x = -9$
3
Divide both sides by 3:
$\frac{3x}{3} = \frac{-9}{3} \ \Rightarrow\ x = -3$
4
Check: put x = -3 back into the equation.
$3\cdot(-3) + 4 = -9 + 4 = -5 \checkmark$

LaTeX source of the formulas on this page

\[ 3x + 4 = -5\ \Rightarrow\ x = -3 \]
\[ 3x + 4 = -5 \]
\[ 3x + 4 - 4 = -5 - 4 \ \Rightarrow\ 3x = -9 \]
\[ \frac{3x}{3} = \frac{-9}{3} \ \Rightarrow\ x = -3 \]
\[ 3\cdot(-3) + 4 = -9 + 4 = -5 \checkmark \]

Trying values of x in 3x + 4 = −5

x	3x + 4	Equals -5?
-5	-11	no
-4	-8	no
-3	-5	yes
-2	-2	no
-1	1	no

Questions

What is x in 3x + 4 = −5?

The solution of 3x + 4 = −5 is x = -3.

How do you solve 3x + 4 = −5?

Subtract 4 from both sides to get 3x = -9, then divide both sides by 3 to get x = -3.

How do I check the answer?

Replace x by -3: 3(-3) + 4 = -5, which is -5.

Solve 3x + 4 = −5

How to work it out

Trying values of x in 3x + 4 = −5

Questions

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