Write an equivalent expression by distributing the "-−" sign outside the parentheses: -(-4.2w-7x-5.4)

4.2*w + 7*x + 5.4

Step-by-step explanation:

Here we need to remember how the product of different signs works, here is the rule:

(+)*(+) = (+)

(+)*(-) = (-)

(-)*(+) = (-)

(-)*(-) = (+)

Now we want to distribute the negative sign in the equation:

"-(-4.2w-7x-5.4)"

We can write this as:

-(-4.2w-7x-5.4) = (-1)*(-4.2w-7x-5.4)

Now we can distribute the "-1"

Then we get:

(-1)*(-4.2w) + (-1)*(-7x) + (-1)*(-5.4)

We have 3 cases where we need to use the "(-)*(-) = (+)" rule, then we get:

(-1)*(-4.2w) + (-1)*(-7x) + (-1)*(-5.4) = 4.2*w + 7*x + 5.4

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.