Solve 7x + 7 = −42

The solution of 7x + 7 = −42 is x = -7.

7x + 7 = -42\ \Rightarrow\ x = -7

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The lines y = 7x + 7 and y = -42 meet at x = -7. 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.
$7x + 7 = -42$
2
Subtract 7 from both sides:
$7x + 7 - 7 = -42 - 7 \ \Rightarrow\ 7x = -49$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{-49}{7} \ \Rightarrow\ x = -7$
4
Check: put x = -7 back into the equation.
$7\cdot(-7) + 7 = -49 + 7 = -42 \checkmark$

LaTeX source of the formulas on this page

\[ 7x + 7 = -42\ \Rightarrow\ x = -7 \]
\[ 7x + 7 = -42 \]
\[ 7x + 7 - 7 = -42 - 7 \ \Rightarrow\ 7x = -49 \]
\[ \frac{7x}{7} = \frac{-49}{7} \ \Rightarrow\ x = -7 \]
\[ 7\cdot(-7) + 7 = -49 + 7 = -42 \checkmark \]

Trying values of x in 7x + 7 = −42

x	7x + 7	Equals -42?
-9	-56	no
-8	-49	no
-7	-42	yes
-6	-35	no
-5	-28	no

Questions

What is x in 7x + 7 = −42?

The solution of 7x + 7 = −42 is x = -7.

How do you solve 7x + 7 = −42?

Subtract 7 from both sides to get 7x = -49, then divide both sides by 7 to get x = -7.

How do I check the answer?

Replace x by -7: 7(-7) + 7 = -42, which is -42.

Solve 7x + 7 = −42

How to work it out

Trying values of x in 7x + 7 = −42

Questions

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