Solve 7x − 9 = 89

The solution of 7x − 9 = 89 is x = 14.

7x - 9 = 89\ \Rightarrow\ x = 14

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The lines y = 7x − 9 and y = 89 meet at x = 14. 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.
$7x - 9 = 89$
2
Add 9 to both sides:
$7x - 9 + 9 = 89 + 9 \ \Rightarrow\ 7x = 98$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{98}{7} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$7\cdot14 - 9 = 98 - 9 = 89 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 9 = 89\ \Rightarrow\ x = 14 \]
\[ 7x - 9 = 89 \]
\[ 7x - 9 + 9 = 89 + 9 \ \Rightarrow\ 7x = 98 \]
\[ \frac{7x}{7} = \frac{98}{7} \ \Rightarrow\ x = 14 \]
\[ 7\cdot14 - 9 = 98 - 9 = 89 \checkmark \]

Trying values of x in 7x − 9 = 89

x	7x − 9	Equals 89?
12	75	no
13	82	no
14	89	yes
15	96	no
16	103	no

Questions

What is x in 7x − 9 = 89?

The solution of 7x − 9 = 89 is x = 14.

How do you solve 7x − 9 = 89?

Add 9 to both sides to get 7x = 98, then divide both sides by 7 to get x = 14.

How do I check the answer?

Replace x by 14: 7(14) − 9 = 89, which is 89.

Solve 7x − 9 = 89

How to work it out

Trying values of x in 7x − 9 = 89

Questions

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