Consecutive numbers are 1 apart
they are
x,x+1,x+2,x+3,x+4
average is 21
(x+x+1+x+2+x+3+x+4)/5=21
(5x+10)/5=21
times both sides by 5
5x+10=105
minus 10 both sides
5x=95
divide both sides by 5
x=19
x+1=20
x+2=21
x+3=22
x+4=23
the smallest number is 19
Check the discriminant (always a good idea).
b^2 - 4ac
b = -19
c = -15
a = 10
(-19)^2 - 4(10)(-15)
361 + 600
961
Yes it can be factored, but if you like, you could use the quadratic formula.
x = [- (-19) +/- sqrt(961)]/(2 * 10)
x = [19 +/- 31 ] / 20
x = (19 + 31/20
x = (50)/20
x = 5/2
x = [19 - 31] / 20
x = [- 12]/20
x = -3/5
Getting the factors is a little tricky.
(x - 5/2)(x + 3/5) = 0
The first factor is found by putting
x - 5/2 in that form and multiplying through by 2
1/2 (2x - 5) The 1/2 comes from multiplying by 2.
The second factor is
1/5 (5x + 3)
So the equation will look like
1/2(2x - 5)1/5(5x + 3) = 0 If you multiply by 2 you get
(2x - 5)1/5(5x + 3) = 0 and now multiply by 5 you get
(2x - 5) (5x + 3)
Check
2x*5x - 25x + 6x - 15
10x^2 - 19x - 15 = 0
So everything works out.
Answer:
About 6 inches tall.
Step-by-step explanation:
One book has a thickness of 2
inches.
Another book has a thickness of 3.56 inches
Converting 2 inches to decimals will give; 2.4285714286 inches
If the books are stacked together, they become 2.4285714286 inches + 3.56 inches = 5.988571429 inches tall or about 6 inches tall (answer rounded up to nearest whole number).
This is known as Einstein's proof, not because he was the first to come up with it, but because he came up with it as a 15 year old boy.
Here the problem is justification step 2. The written equation
BC ÷ DC = BC ÷ AC
is incorrect, and wouldn't get us our statement 2, which is correct.
For similar triangles we have to carefully pair the corresponding parts to get our ratios right:
ABC ~ BDC means AB:BD = BC:DC = AC:BC so BC/DC=AC/BC.
Justification 2 has the final division upside down.
Answer:
you will know because it you do the system of whatever thingy and there are no two dots in the same row and the line is straight in either a negative or positive slope at a diagonal the equation is linear and its a function.
Step-by-step explanation:
The image is an example of a linear equation that is both a function and positive lenear
