-12x + 11y = -53
-11x -6y = -129
Solve systems graphically and algebraically

-12x + 11y = -53

×= 4.67

y= -4.81

-11x - 6y = -129

x= 11.73

y= 21.5

Step-by-step explanation:

-12x + 11 (0) = -53

-12x = -53

-53/-12 = 4.67

4.67 = x

-12(0) + 11y = -53

-53/11 = -4.81

-4.81 = y

-11x - 6(0) = -129

-129/-11 = 11.73

11.73 = x

-11(0) -6y = -129

-129/-6y = 21.5

21.5 = y

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 ☺

the answer is 13 cm