Solve each of the following: a) x² + 4x – 77 = 0
b) x(x + 4) = -2(3x + 8)
Please show your work

a.) x=7 or x=-11

b.) x=−2 or x=−8

Step-by-step explanation:

a)  x² + 4x – 77 = 0

Step 1: Factor left side of equation.

(x−7)(x+11)=0

Step 2: Set factors equal to 0.

x−7=0 or x+11=0

x=7 or x=−11

b.) x(x + 4) = -2(3x + 8)

Step 1: Simplify both sides of the equation.

x^2+4x=−6x−16

Step 2: Subtract -6x-16 from both sides.

x^2+4x−(−6x−16)=−6x−16−(−6x−16)

x^2+10x+16=0

Step 3: Factor left side of equation.

(x+2)(x+8)=0

Step 4: Set factors equal to 0.

x+2=0 or x+8=0

x=−2 or x=−8

a) {-11, 7}.

b) {-8, -2}

Step-by-step explanation:

a) x^2 + 4x - 77 = 0

To factor this we need 2 numbers whose product is -77 and sum is + 4.

They are + 11 and - 7, so:

( x + 11)(x - 7) = 0

x + 11 = 0 or x - 7 = 0

x = -11,  7.

b) x(x + 4) = -2(3x + 8)

x^2 + 4x = -6x - 16

x^2 + 4x + 6x + 16 = 0

x^2 + 10x + 16 = 0

(x + 2)(x + 8) = 0

x = -8, -2.

step-by-step explanation: so we look at the formula un = a + (n-1)d

un is the amount of seats

n is the nth term aka row number

a is the original sequence/row number

d is the difference between each term

so in this a=22 d=6 and n can remain as n because we are simply formjng a rule

lets put these in the equation

un=22+(n-1)(6)

this is your answer to part a

however

lets double check that this is correct, we'll try putting it into the second term

un=a+(n-1)d

u2=22+(2-1)(6)

u2=22+6

u2=28

as the question said the second row has 28 seats so now we know the formula we made is correct.

as for part b

un=a+(n-1)

its asking us to find a row with 100 seats.

remember un was the amount of seata so all we do is substitute this in.

un=100 a=22 d=6

un=a+(n-1)d

100=22+(n-1)(6)

so now we simplify to find n which is the row number.

100-22=22+(n-1)(6)-22

78=(n-1)(6)

78/6=(n-1)(6)/6

13=n-1

13+1=n-1+1

14=n

so now we know that in the 14th row there is 100 seats.

hope this and that you understood! its my first time using the app or anyone out on here : p its also me to revise so a bunch! ask more questions if you dont understand ☺