Answer:
x = 21
Step-by-step explanation:
3x + 18 + 4x + 15 = 180
7x + 33 = 180
7x = 147
x = 21
A, D, and E are true
One X on the line plot marks one time something happened. So the two x’s above the 1 means that he practiced piano for one hour (see to the right that says hours next to the numbers, so 1=1 hour) two times.
45 minutes is 3/4 of an hour, and is the mark right between 1/2 and 1. There is one x above this mark, so that means Thaddeus practiced for 45 minutes one time, so B is false
Thadeus practiced piano for 30 minutes two times, so C is false because he didn’t mostly practice for thirty minutes.
D is correct because there are 2 Xs above the 0, which means two times he practiced for zero hours, which means he didn’t practice at all.
E is correct because 15 minutes is 1/4 of an hour, so it is the mark between 0 and 1/2. We see there are three x’s there, so that means he practiced for 15 minutes 3 times.
I hope this helps! Let me know if you want me to explain it differently.
Let x = # of 25-cent stamps
y = # of 2-cent stamps
{ x+ y = 88
{ 0.25x + 0.02y = 15.56
60 25-cent stamps 28 2-cent stamps
Numerical expressions contain numbers, while algebraic expressions contain variables and numbers.
<u>Numerical Expression</u>
"Difference" indicates that we'll be subtracting 13 from 48.
48 - 13 = 35
<u>Algebraic Expression</u>
Variables represent the unknown number, in this case the difference between 48 and 13. Let d represent the difference between the two.
48 - 13 = d
35 = d
Rewriting the formula in standard form would be x^2-8x+14=0
