Please need help on this

babunello [35]

To evaluate this expression, we need to remember that subtracting a negative number is the same as adding a positive number, and that adding a negative number is the same as subtracting a positive number. Using this knowledge, let's begin to simplify the expression below:

-1 - 3 - (-9) + (-5)

Because addition of a negative number is the same as subtraction of a positive number, we can change + (-5) to -5, as shown below:

-1 - 3 - (-9) - 5

Next, because we know that subtracting a negative number is the same as adding a positive number, we can change - (-9) to + 9, as shown below:

-1 - 3 + 9 - 5

Now, we can subtract the first two terms and begin to evaluate our expression:

-4 + 9 - 5

Next, we can add the first two numbers of the expression:

5 - 5

Now, we can subtract our last two numbers, which gives us our answer:

0

Therefore, your answer is 0.

Hope this helps!

3 0

3 years ago

3x^2 + 4x = -8<br> solve using quadratic formula

Firdavs [7]

Use the quadratic equation to solve this (image of the quadratic equation is below)

Remember that quadratic functions are set up like so:

$ax^{2} +bx +c = 0$

To make the equation 3x² + 4x = -8 into a quadratic function you must bring -8 to the left side of the equation so it equals zero. To do this add 8 to both sides

3x² + 4x + 8= -8 + 8

3x² + 4x + 8 = 0

That means that in this equation...

a = 3

b = 4

c = 8

^^^Plug these numbers into the quadratic equation and solve (Keep in mind that +/- is ± )

$\frac{-4+/-\sqrt{(4)^{2}-4(3)(8)}}{2(3)}$