<span>This is a simple subtraction question. To find the answer, you simple need to subtract 15 from 104. This equals 89, so there were 89 4th graders at school that day in total. In the instance you're unsure that a subtraction equation is right, you can also add your answers back together to double check, so 89 + 15 = 104.</span>
For the arithmetic sequence
a₁, a₂, a₃, ...,
the n-th term is

where d = the common difference
Because a₅ = 12.4,
a₁ + 4d = 12.4 (1)
Because a₉ = 22.4,
a₁ + 8d = 22.4 (2)
Subtract (1) from (2).
a₁ + 8d - (a₁ + 4d) = 22.4 - 12.4
4d = 10
d = 2.5
From (1),
a₁ = 12.4 - 4*2.5 = 2.4
Therefore
a₃₁ = 2.4 + 30*2.5 = 77.4
Answer: a₃₁ = 77.4
Answer:
number of shells zoe gives to dev = 7
number of shells zoe is left with = 55-7= 48
number of shells dev has = 9+7=16
Step-by-step explanation:
let the initial number of shells that dev has be A, and initial number of shells that zoe has be B.
let the number of shells that zoe gives to dev be x.
after giiving x shells zoe is left with 3 times the number of shell as that of dev.
therefore number of shells with zoe = 3×number of shells with dev.
number of shells with zoe = initial shells - x = 55-x
number of shells with dev = initial shells + number of shells he gets
= 9+x
therefore (55-x)=3×(9+x)
55-x = 27+3x
55-27=3x+x
4x = 28
x= 7
therefore number of shells zoe gives to dev = 7
number of shells zoe is left with = 55-7= 48
number of shells dev has = 9+7=16
Answer with Step-by-step explanation:
We are given that

For each real number 
To prove that f is one -to-one.
Proof:Let
and
be any nonzero real numbers such that

By using the definition of f to rewrite the left hand side of this equation

Then, by using the definition of f to rewrite the right hand side of this equation of 

Equating the expression then we get




Therefore, f is one-to-one.
Answer:
Step-by-step explanation:
given are four statements and we have to find whether true or false.
.1 If two matrices are equivalent, then one can be transformed into the other with a sequence of elementary row operations.
True
2.Different sequences of row operations can lead to different echelon forms for the same matrix.
True in whatever way we do the reduced form would be equivalent matrices
3.Different sequences of row operations can lead to different reduced echelon forms for the same matrix.
False the resulting matrices would be equivalent.
4.If a linear system has four equations and seven variables, then it must have infinitely many solutions.
True, because variables are more than equations. So parametric solutions infinite only is possible