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the error interval for the number is:

12.25<= x < 12.35 



Maths

A number x rounded to 1 decimal place is 12.3

You would use the quadratic formula: 
x = -b +- square root of b^2 - 4ac / 2a 

ax^2 + bx + c = 0
4x^2 - 2x - 15 = 0
using this we know that a = 4, b = -2 and c = -15 

the we substitute those values into the equation on a calculator:

x = -(-2) + square root  (-2)^2 - 4(4)(-15) / 2(4)

x = -(-2) - square root  (-2)^2 - 4(4)(-15) / 2(4)

this gives x to be x = 1 +- square root 61 / 4

What are the values of x using the factorization method in 4x^2 - 2x -15=0

This question cannot be answered as there is insufficient information.

3n+4

This is actually really simple 
for the first term you substitute 1 into n:
25 - 3(1) 
25 - 3 = 22
for the second term you substitute 2 into n:
25 - 3(2)
25 - 6 = 19
for the third term you substitute 3 into n:
25 - 3(3)
25 - 9 = 16
so the first three terms in the sequence are 22, 19, 16

I hope this helped :)

Simran Dhillon

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Simran Dhillon