Answer:
![x=4](https://img.qammunity.org/2020/formulas/mathematics/high-school/hxnxycp7ditjozikbfiiya3nb2g21vrzay.png)
Explanation:
You need to find the value of the variable "x".
To solve for "x", the first step is to apply the Subtraction property of equality, which states that:
![If\ a=b\ then\ a-c=b-c](https://img.qammunity.org/2020/formulas/mathematics/high-school/58bqkb1e7ly9pnsjyeaupctubsn200q3qu.png)
Then, you need to subtract 4 from both sides of the equation:
![3x + 4 = 16\\3x + 4-4 = 16-4\\3x=12](https://img.qammunity.org/2020/formulas/mathematics/high-school/u0c4s09z0791dyt3e1e00xkk7dmj9vw4ob.png)
And finally, you can apply the Division property of equality, which states that:
![If\ a=b\ then\ (a)/(c)=(b)/(c)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/t48t3u02cpytapoo3hy49d3ivc8d06suj2.png)
Then you can divide both sides of the equation by 3, getting:
![(3x)/(3)=(12)/(3)\\\\x=4](https://img.qammunity.org/2020/formulas/mathematics/high-school/oqya5wozhqs1otxirkowv6npsn6bzajirt.png)