Solve 7x + 15 = −27

The solution of 7x + 15 = −27 is x = -6.

7x + 15 = -27\ \Rightarrow\ x = -6

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The lines y = 7x + 15 and y = -27 meet at x = -6. 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.
$7x + 15 = -27$
2
Subtract 15 from both sides:
$7x + 15 - 15 = -27 - 15 \ \Rightarrow\ 7x = -42$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{-42}{7} \ \Rightarrow\ x = -6$
4
Check: put x = -6 back into the equation.
$7\cdot(-6) + 15 = -42 + 15 = -27 \checkmark$

LaTeX source of the formulas on this page

\[ 7x + 15 = -27\ \Rightarrow\ x = -6 \]
\[ 7x + 15 = -27 \]
\[ 7x + 15 - 15 = -27 - 15 \ \Rightarrow\ 7x = -42 \]
\[ \frac{7x}{7} = \frac{-42}{7} \ \Rightarrow\ x = -6 \]
\[ 7\cdot(-6) + 15 = -42 + 15 = -27 \checkmark \]

Trying values of x in 7x + 15 = −27

x	7x + 15	Equals -27?
-8	-41	no
-7	-34	no
-6	-27	yes
-5	-20	no
-4	-13	no

Questions

What is x in 7x + 15 = −27?

The solution of 7x + 15 = −27 is x = -6.

How do you solve 7x + 15 = −27?

Subtract 15 from both sides to get 7x = -42, then divide both sides by 7 to get x = -6.

How do I check the answer?

Replace x by -6: 7(-6) + 15 = -27, which is -27.

Solve 7x + 15 = −27

How to work it out

Trying values of x in 7x + 15 = −27

Questions

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