Answer: 1 + 2x
Explanation:
To solve this problem, it's helpful to understand "order of operations." The order is: parentheses, exponents, multiplication, division, addition, and lastly, subtraction.
A helpful mnemonic is PEMDAS. I was taught "Parachute Expert My Dear Aunt Sally" to help remember the order.
We must work with the numbers inside the parantheses, since "parantheses" is the first operation. We'll start with the first paranthesis: (-5x2 + 10x - 12).
Since there are no exponents in this equation, we can go to the third operation: multiplication. (I like to use the "·" symbol to show that two numbers are multiplied because it's easy for me to confuse the letter X with "x" when it is used as a multiplication symbol).
-5 · 2 = -10
Two negative numbers are added, so -10 and -12 = -22
This leaves (-22 + 10x)
The -22 and 10x are not added together because numbers without a letter cannot be added to numbers with letters.
Now we'll work with the second paranthesis: (-4 · 2 + 8x - 15)
-4 · 2 = -8
-8 and -15 is added to make -23
The paranthesis now looks like:
(-23 + 8x)
Notice that there is a negative sign outside of the second paranthesis in the equation.
(-22 + 10x) − (-23 + 8x)
When a number or symbol is outside of a paranthesis, that number or symbol is multiplied across everything within the parantheses.
Now, it is:
(23 - 8x)
All of the numbers can be taken out of the parantheses now:
-22 + 10x + 23 - 8x
-22 + 23 = 1
10x - 8x = 2x
The final answer:
1 + 2x
Hope this helps!