Answer:
Option A - 
Step-by-step explanation:
We have given the expression 
We have to find the value of the expression ?
Solution :
Step 1 - Write the expression

Step 2 - Applying symbol rule i.e. multiplication of positive into negative is always negative, 

Step 3 - Solve

Therefore, The value of the expression is 
So, Option A is correct.
Answer:
3x + 4y = 16 The rule is you can do any valid operation on both sides of an equation and it will still be equal. Subtract 4y.
3x = -4y + 16 Divide by 3.
x = -4y/3 + 16/3 Answer B.
Answer:
$63.75
Step-by-step explanation:
15% off
Get percentage of retail price
1-0.15 = .85
0.85 = 85%
The sale price is 85% of the retail price
Multiply
0.85 * 75
$63.75
2.21 x 10^17 and the answer is 2.21e+17
When you multiply it is just 5*23=115
115*2= 230