What is the mistake in this problem and why is it wrong? 15+(√9•7)÷13 = 15+(3•7)÷3 = 15+(21)÷3 = 36+3 =12

[Edit:}

Okay! So after you have 15+(21)÷3, you have to remember PEMDAS.

PEMDAS is the order in which you solve equations.

1. Parentheses: you solve everything in the parentheses first, all while following the rules of PEMDAS

2. Exponents: after you solve the things in the parentheses, you do the exponents.

3. Then you do Multiplication or Division, solving in the order from left to right.

4. After, you do Addition or Subtraction, solving in the order from left to right.

So using PEMDAS, we'll solve 15+(21)÷3.

We do division before addition, so 21/3 is 7.

Then you add 15 to 7 and get 22 as your final answer.

Hope this helps!

europa2433

europa2433

step-by-step explanation:

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 ☺