If f(x)=4x3+3x2−5x+20 and g(x)=9x3−4x2+10x−55, what is (g−f)(x)?

A) 5x3−7x2+15x−75
B) 5x3+x2+5x+35
C) 13x3−x2+5x−35
D) −5x3+7x2−15x+75

Step-by-step explanation:

(g-f)(x) = 9x³ - 4x² + 10x - 55 - [ 4x³ +3x² - 5x + 20]

To remove the parenthesis, take - inside, multiply f(x) by -1

= 9x³ - 4x² + 10x - 55 -  4x³ - 3x² + 5x - 20  

Now, bring like terms together,

= 9x³ - 4x³ - 4x² - 3x² + 10x + 5x - 55 - 20

= 5x³ - 7x² + 15x - 75

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this

the answer is a

step-by-step explanation: