Dr. marshall mixed 11.256 g of chemical a, 13.151 g of chemical b, and 8.607 g of chemical c to make 4 doses of medicine. round the weight of chemical a to the nearest gram.

The weight of chemical A to the nearest gram is 11 g

Step-by-step explanation:

we know that

To Round a number

a) Decide which is the last digit to keep  

b) Leave it the same if the next digit is less than (this is called rounding down)  

c) But increase it by   if the next digit is   or more (this is called rounding up)

In this problem we have

We want to keep the digit

The next digit is 2 which is less than , so no change is needed to

therefore

The weight of chemical A to the nearest gram is 11 g

starting with:    

5 + x - 12 = 2x - 7   

5 + x - 12 - x = 2x - 7 - x (subtract x from both sides)   

5 - 12 = x - 7 (combine and cancel x's from both sides)   

5 - 12 + 7 = x - 7 + 7 (add 7 to both sides)   

0 = x (add numbers together on both sides)       

so in order for the equation to be true, x must be 0.   

trying x = -0.5   

5 + x - 12 = 2x - 7 (original equation)   

5 + -0.5 - 12 = 2(-0.5) - 7 (plug in value of x)   

5 + -0.5 - 12 = -1 - 7 (did multiplication)   

-7.5 = -8 (did addition on both sides)       

since -7.5 is obviously not equal to -8, the value of -0.5 for x is wrong.   

trying x = 0   

5 + x - 12 = 2x - 7 (original equation)   

5 + 0 - 12 = 2(0) - 7 (plug in value of x)   

5 + 0 - 12 = 0 - 7 (did multiplication)   

-7 = -7 (did addition on both sides)       

since -7 equals -7, that demonstrates that the value of 0 for x is correct.   

trying x = 1   

5 + x - 12 = 2x - 7 (original equation)   

5 + 1 - 12 = 2(1) - 7 (plug in value of x)   

5 + 1 - 12 = 2 - 7 (did multiplication)   

-6 = -5 (did addition on both sides)       

since -6 is obviously not equal to -5, the value of 1 for x is wrong.

12

step-by-step explanation:

12 + 5 = 17

12x2=24

24-7=17