Answer:

Step-by-step explanation:
A quick review on PEMDAS, the order of how to solve an equation:
P - parentheses. When parentheses are being used, you have to do everything inside them before doing everything outside of them.
E - exponents. We'll skip these, since there aren't any exponents we need to worry about in this equation.
M/D - multiplication/division. I include these both together because they can be done at the same time.
A/S = addition/subtraction. Can also be done at the same time.
Some other things to note:
You add all the things with an x attached to it, and you add all the things without an x attached to it, and these never cross.
When you bring something from one side of an equal sign to another, you make it negative.
Let's solve for x using what we've learned:

Answer: x = 4
Step-by-step explanation:
2x - 3 + 4x = 21
6x - 3 = 21
6x - 3 (+3) = 21 (+3)
6x = 24
24/6
x = 4
Answer with Step-by-step explanation:
We are given that
u+ v and u-v are orthogonal
We have to prove that u and v must have the same length.
When two vector a and b are orthogonal then

By using the property

We know that



Magnitude is always positive
When power of base on both sides are equal then base will be equal
Therefore,

Hence, the length of vectors u and v must have the same length.
Answer: Expression represents the number of text messages you sent on Tuesday = 2x
Expression represents the number of text messages you sent on Wednesday = 12+2x
Expression represents the number of text messages you sent on Thursday = x+6
Step-by-step explanation:
Given:
Number of text messages sent on Monday = x
On Tuesday, Number of text messages sent = 2 (Number of messages sent on Monday)
= 2 x
On Wednesday, Number of text messages sent = 12+ (Number of messages sent on Tuesday)
= 12 +2x
On Thursday, Number of text messages sent = 
= x+6
Expression represents the number of text messages you sent on Tuesday = 2x
Expression represents the number of text messages you sent on Wednesday = 12+2x
Expression represents the number of text messages you sent on Thursday = x+6
143 cards, you can find this using the LCM or least common multiple. <span />