400-3x=112
3x=400-112=288
x=96
He is 96 years old.
Answer:90%
Step-by-step explanation: we know this because the total about of questions on the test is 20 and for the score to add up to 100% each question has to be worth 5% so we can just do 5 x 18 to get 90%. or (5 x 2) - 100 to also get 90%
The value of the sum of twice a number and 7 is 17.
<h3>What is an expression?</h3>
An expression is used to show the relationship between the variables that are given.
Let the number in this situation be 5. This will be illustrated as:
2n + 7
where n = number = 5
= 2n + 7
= 2(5) + 7
= 10 + 7
= 17
Therefore, the number is 17.
Learn more about numbers on:
brainly.com/question/24644930
#SPJ1
<h3>hello!</h3>
==========================================================
Let's simplify the expression:-
Multiply 3 times 1 and 1 times 2:-
======================================================
<h3>note:-</h3>
Hope everything is clear; if you need any clarification/explanation, kindly let me know, and I'll comment and/or edit my answer :)
Where the heck did x come from!
