I need some algebra help!
1. d^2 + 18d + 81

A) (d+9)(d-9)
B) (d+9)^2
C) (d-81)(d-1)
D) (d-9)^2

2. d^2 - 13d + 30

A) (d+10)(d+3)
B) (d+10)(d-3)
C) (d-10)(d+3)
D) (d-10)(d-3)

3. r^2 - 49

A) (r-7)(r+7)
B) (r+7(r+7)
C) (r-7)(r-7)
D) (r-7)(r+9)

Question

I need some algebra help!
1. d^2 + 18d + 81

A) (d+9)(d-9)
B) (d+9)^2
C) (d-81)(d-1)
D) (d-9)^2


2. d^2 - 13d + 30

A) (d+10)(d+3)
B) (d+10)(d-3)
C) (d-10)(d+3)
D) (d-10)(d-3)


3. r^2 - 49

A) (r-7)(r+7)
B) (r+7(r+7)
C) (r-7)(r-7)
D) (r-7)(r+9)

jango_in_dtown · Answer

1. d^2 + 18d + 81=d^2 +9d +9d +81=d(d+9)+9(d+9)=(d+9)^2

jango_in_dtown · Answer

hints 81=9*9

hwyl · Answer

LOOKS LIKE YOU NEED TO FIGURE OUT THE MIDDLE AND LAST TERM
THINK OF TWO NUMBERS THAT ADDS UP TO 18 AND YIELDS 81 WHEN MULTIPLIED TO EACH OTHER

anonymous · Answer

A C B C

anonymous · Answer

@jango_IN_DTOWN  So number 1 is B?

anonymous · Answer

ignore the last c ;)

jango_in_dtown · Answer

yes

jango_in_dtown · Answer

2.d^2 - 13d + 30 i will give hints -13=-10+(-3)
and 30=(-10)*(-3)

jango_in_dtown · Answer

3. 49=7^2 and so use the formula of a^2-b^2= (a+b)(a-b)