Simplify (10x^2-19x-2) + (5x^2-8x+13) - (3x^2-2)

12x² -27x + 13

Step-by-step explanation:

First of all, expand the first two brackets and put the correlating values near each other:

10x² + 5x² -19x -8x -2 +13

10x² + 5x² = 15x²

-19x + - 8x = -27x

-2 + 13 = 11

15x² - 27x + 11

Now, subtract the values inside the third bracket:

15x² - 3x² = 12x²

11 - -2 = 11 + 2 = 13

So the end result is:

12x² -27x + 13

Part a)

Part b)

Step-by-step explanation:

step 1

Find the measure of angle ACB

we know that

The sum of the measures of interior angle of a triangle must be equal to

so

In the triangle ABC

step 2

Find the measure of angle ACD

we know that

-------> by supplementary angles

we have

substitute

step 3

Find the measure of angle CED

we know that

m<DCE=m<ACB ------> by vertical angles

so

Remember that

The sum of the measures of interior angle of a triangle must be equal to

so

In the triangle CDE