Answer:
9
Step-by-step explanation:
7r+18=r²
r²-7r-18=0
factorizing
r²+2r-9r-18=0
r(r+2)-9(r+2=0
(r-9)(r+2)=0
r-9=0
r=9
check
(r²)=(9*9)=81
7r+18=7(9) + 8=81
Answer:
243.6
Step-by-step explanation:
Answer:
3x³ + x² - 2
Step-by-step explanation:
a) 3(x squared plus 3x cubed - 2)
x squared = x²
3x cubed = 3x³
3(x squared plus 3x cubed - 2)
= 3(x² + 3x³ - 2)
= 3x² + 9x³ - 6
Rearrange according to power
= 9x³ + 3x² - 6
When the expression is divided by 3, it is equivalent to
3x³ + x² - 2
