Can anyone answer these questions

see explanation

see explanationStep-by-step explanation:

21

Note that

(a - )²

= a² - 2 +

= a² + - 2

= 11 - 2

= 9

Thus

(a - )² = 9 ( take the square root of both sides )

a - = 3

22

Since the expression is a perfect square, then

(4x + 5y)²

= 16x² + 40xy + 25y²

Comparing coefficients, then

a - 1 = 40 ( add 1 to both sides )

a = 41

23

99² - 87² ← is a difference of squares and factors as

= (99 - 87)(99 + 87)

= 12 × 186 = 1152, thus

24a = 1152 ( divide both sides by 24 )

a = 48

hey there!

if she's saving for six months, let's divide the total number we need for the trip by six, dividing it into the amount that needs to be saved for each month.

500 ÷ 6 =

she needs to save at least this amount each month, so we should use this symbol: ≥

let x be the amount she saves each month.

your final answer is x ≥

hope this !

x = ± 6i

step-by-step explanation:

x^2 = -36

take the square root of each side

sqrt(x^2) = sqrt(-36)

we know sqrt(ab) = sqrt(a) sqrt(b)

x = ±sqrt(36) sqrt(-1)

we know that sqrt (-1) = i

x = ± 6i