Consider this equation.
7.8 + 2(0.75m + 0.4) = -6.4m + 4(0.5m - 0.8)
mia solved the equation and determined that m = 2. is she correct?
a. she is incorrect because when substituting 2 for m the result was a true statement.
b. she is incorrect because when substituting 2 for m the result was a false statement.
c. she is correct because when substituting 2 for m the result was a true statement.
d. she is correct because when substituting 2 for m the result was a false statement.

B if m=2

(Just to make sure that isn't m=-2, right?)

Step-by-step explanation:

7.8 + 2(0.75m + 0.4) = -6.4m + 4(0.5m - 0.8)  

Let's plug in 2 for m.

7.8+2(0.75*2+0.4)  = -6.4*2+4(0.5*2-0.8)

If 2 is a solution, then both sides will be the same.

If 2 is not a solution, then both sides will be different.

If both sides are the same, it is a true equation.

If both sides are different, it is a false equation.

Let's simplify 7.8+2(0.75*2+0.4)

According to PEMDAS, we must perform the operations in the parenthesis.

We have multiplication and addition in ( ).  We will do the multiplication because the MD comes before the AS.

0.75*2=1.5

So now our expression 7.8+2(0.75*2+0.4) becomes 7.8+2(1.5+0.4)

Now to do the addition in the ( ).

1.5+0.4=1.9.

So now our expression 7.8+2(0.75*2+0.4) becomes 7.8+2(1.9).

We have multiplication to be perform now because again MD becomes before AS.

7.8+2(0.75*2+0.4) becomes 7.8+3.8

Last step perform the addition (the only operation left here on the left hand side)

7.8+2(0.75*2+0.4) becomes 11.6 .

Let's focus on the right now.

-6.4*2+4(0.5*2-0.8)

-6.4*2+4(1       -0.8)  I did the multiplication in the ( ) first.

-6.4*2+4(.2)              I did the subtracting in the ( ).

-12.8+.8                    I did the multiplication by -6.4*2 and 4*.2 simultaneously

-12

I'm going to put all of this together because I think it might be easier to read:

7.8 + 2(0.75m + 0.4) = -6.4m + 4(0.5m - 0.8)  

Plug in 2 for m

7.8 + 2(0.75*2  + 0.4)=-6.4*2 + 4(0.5*2 - 0.8)

7.8 + 2(1.5        + 0.4)= -6.4*2 + 4(1       -0.8)

7.8 + 2(1.9)                = -6.4*2 + 4(.2)

7.8 +  3.8                 =   -12.8  +.8

11.6                          =-12

This is false because 11.6 is not the same as -12.

m=2 leads to a false equation

B.

24

step-by-step explanation:

the graph shows 30% of students walk. 80 students were questioned, so the number that said they walk is

30% × 80 = 0.30 × 80 = 24

after 1 year: 221 deer

step-by-step explanation:

30% of 170 is 51. 170+51=221