Answer:
option 4
Step-by-step explanation:
(f*g)(x) =(x² + x+ 1)*(x² - x -1)
= x²*(x² - x -1) + x(x² - x -1) + 1*( x² - x -1)
= x²*x² - x²*x -x²*1 + x*x² - x*x -x*1 + x² - x -1
= x⁴ - x³ - x² +x³ - x² - x + x² - x -1
= x⁴ - x³ + x³ - x² - x² + x² - x - x - 1
= x⁴ - x² - 2x - 1
Let x be the number multiplied by 7.
We get 7x.
At least 30 means GREATER THAN OR EQUAL TO 30 or ⩾ 30.
Put it all together now.
7x ⩾ 30
Divide both sides by 7.
x ⩾ 30/7
Done!
The answer is has to be D