Question

sendo A=4X² - 5X + 12, B= 2X + 1 e C= 5X² - 1, CALCULE

a) A+B+C

b) B-C

Answer 1

A + B + C =
4x² - 5x + 12 + 2x + 1 + 5x² - 1 =
9x²  - 3x + 12 ***

b
B - C
( 2x + 1) - ( 5x² - 1) =
2x + 1 - 5x² + 1 =
-5x² + 2x + 2 =
5x² - 2x - 2 ***

Answer 2

Vamos lá :

A = 4x² - 5x + 12   ;;  B = 2x + 1 e C = 5x² - 1

a) A + B + C

= (4x² - 5x + 12) + (2x + 1) + (5x² - 1)
= 4x² - 5x + 12 + 2x + 1 + 5x² - 1
= 4x² + 5x² - 5x + 2x + 12 + 1 - 1
= 9x² - 3x + 12

b) B - C

= (2x + 1) - (5x² - 1)
= 2x + 1 - 5x² + 1
= - 5x² + 2x + 1 + 1
= - 5x² + 2x + 2

Espero ter ajudado !!!!