I might be wrong but I think the answer would be -x+2x+6 as a simplified version because if you use the equation (x+4•x+3)-3x(x+1)=a (or any letter you choose), you will get 3x+x^2+12+4x-3x-3x^2=y. Then, you can combine like terms:
4x-2x+12=a
So... the radiator has 15 liters of 70% antifreeze.. but needs an 80% antifreeze
well, so, you need to drain some and put some with higher percentage, seems to be, you will end up at the same 15 liters, possible the radiator's capacity, of 80% antifreeze
so, the same amount going out, of 70% is the same amount going in, of 100% antifreeze
now.. let's use the decimal format for the percents, or 70% is 70/100 or 0.7 and so on

so.. let's subtract, from the current solution, 0.7x and add 1x or x, our antifreeze concentration amount, should be 12 though
10.5 - 0.7x + x = 12
solve for "x"
Answer:
The length of side of largest square is 15 inches
Step-by-step explanation:
The given suares are when joined in the way as shown in picture their sides form a right agnled triangle.
Area of square 1 and perimeter of square 2 will be used to calculate the sides of the triangle.
So,
<u>Area of square 1: 81 square inches</u>

<u>Perimeter of square 2: 48 inches</u>

We can see that a right angled triangle is formed.
Here
Base = 12 inches
Perpendicular = 9 inches
And the side of largest square will be hypotenuse.
Pythagoras theorem can be used to find the length.

Hence,
The length of side of largest square is 15 inches
The correct answer is -1.
In order to solve this, we need to split into the positive and negative version of the answers. Let's start with the positive version.
2 - x < 4
-x < 2
x > -2 ----> NOTE: When we divide by -1, we have to change the direction of the sign.
Now we'll do the negative version.
2 - x > -4
-x > -6
x < 6
So we know the number must be greater than -2, but less than 6. The only number on this list that fits that is -1.