Okay, the equation would be 12 - 2x = 8(x + 4), you got close!
what i would do first is distribute to get rid of those evil parenthesis and make this all simple ^-^
So, we take 8 times x, and 8 times 4.
Our equation, is now 12 - 2x = 8x + 32
Now, what i would do, is simplify it. Get x to one side, and a whole number to the other. Well, for me it would be easier to keep the larger number on the right, and x on the left!
So we have to be fair, and keep it equal! So, i would start with.... subtracting 32. Since its a positive 32, to cancel it out we have to subtract 32, to get to zero! so, by subtracting 32 on both sides ( 12 - 32 and 32 - 32) we end up with -20 - 2x = 8x
Now looking at - 20 - 2x = 8x, i can see what i need to do. i need to get x to one side, and whole numbers to the other. There are no whole numbers on the right, just variables and coefficients, so i have to get that x away from the left!
So, im going to add 2x on both sides, to eliminate it! So we add 2x on the left to cancel it out, and add 2 x on the right to balance it out! We are now left with -20 = 10x
Now what we do is we get rid of that tag along right by the x! Yep, that little 10 there! He has to go!
How to we get rid of him? Well, he is being multiplied by the x! So, we have to do the opposite and divide to get him alone. So, we divide by 10 on both sides, and we are left with -2 = x!
Now, time to check your answer! Basically, you replace x with -2 in the equation! Here we go:
12 - 2(-2) = 8(-2 + 4)
First we should start with multiplying! when we multiply the -2 in the equation, we get 12 + 4 = 8(2), and we can finish that off by simplifying it to 12 + 4 = 16
when we simplify it and add 12 + 4, we get 16. So we are left with 16 = 16.
This equation is true, so we are right! -2 DOES equal x!
2.) I would say something about how the A in front of cos in the equation would change to 90, rather than stay 75 (in the equation for the step by step), but it would be easier to just use the Pythagorean theorem.
Step-by-step explanation:
I think we may have the same class so hopefully this helps:
1.) --> law of cosines formula.
--> plugged in numbers; when you draw the triangle, the included angle would be A, and the opposite side would be a. B and b, and C and c are opposite each other. In this case, a is the hypotenuse.
--> in between steps.
--> more simplifying.
--> answer
2.) This one is just an explanation: The 75 in the equation is the given angle, which is a. If this changes, it would just change in the equation too. And obviously, if it's 90 degrees, you can just use Pythagorean theorem a^2+b^2=c^2.
A number is rational if it can be written in form a/b where a and b are integers and b is not equal to 0 integers are like -4,-3,-2,-1,0,1,2,3,4, etc
so √20=2√5 which is irrational because we can't write it as a fraciton with only integers
also a rational number multilied by an irratinonal number=irrtaional we know that the square root of any prime number will be irrational and 5 is prime so 2 times √5=rational times irrational=irrational