This can either be done by multiplying with 125% (1.25) or, by dividing by dividing on 4 and adding a part.
This is the easiest way, tho.
60*1.25=75
The correct answer is 75 mph.
If A and B are equal:
Matrix A must be a diagonal matrix: FALSE.
We only know that A and B are equal, so they can both be non-diagonal matrices. Here's a counterexample:
![A=B=\left[\begin{array}{cc}1&2\\4&5\\7&8\end{array}\right]](https://tex.z-dn.net/?f=A%3DB%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D1%262%5C%5C4%265%5C%5C7%268%5Cend%7Barray%7D%5Cright%5D)
Both matrices must be square: FALSE.
We only know that A and B are equal, so they can both be non-square matrices. The previous counterexample still works
Both matrices must be the same size: TRUE
If A and B are equal, they are literally the same matrix. So, in particular, they also share the size.
For any value of i, j; aij = bij: TRUE
Assuming that there was a small typo in the question, this is also true: two matrices are equal if the correspondent entries are the same.
I'm assuming you want us to solve for the unknown variable z

Combine like terms on the right side

Use the distributive property on the left side

Add both sides by 20 to cancel out the "-20" on the left side

Divide both sides by 10

That is the value of the known variable, z, in this equation. Let me know if you need any clarifications, thanks!
~ Padoru
What if I write the equation like this:
y = zero x - 3.
Now you know that the slope of the line is zero and its y-intercept is -3.
That's a horizontal line that crosses the y-axis at -3. And just like the equation says, the value of 'y' doesn't depend on 'x'. It's -3 everywhere.
Let x = # of Republicans
x + 4 = # of Democrats
x + x + 4 = 100
x = 48
48 + 4 = 52
There are 52 Democrats and 48 Republicans.