Question

Find m(5) using direct substitution:
m(x)=x+x^2-1
m(5)=(5)+(5)^2-1

How do you do direct substitution?

Answer 1

@DemolisionWolf do you know what "direct substitution" is?

Answer 2

cant really explain with this situation sorry.

Answer 3

1 sec

Answer 4

@ali1029 this guy was getting mad at me for asking him to stop handing out answer while i'm trying to teach ^_^ haha
direct substitution is what you show in the question post

Answer 5

@ali1029 I dont see any other possible way you can do anytype of substitution aside from what you've done, sythetic or direct or whatever

Answer 6

yeah @DemolisionWolf is right. you substituted 5 in for x, that's an example of direct substitution.

Answer 7

haha well thats crazy! you're supposed to actually learn the material :p & okay, so even though it specifically says to use "direct substitution" I could just do m(5)=(5)+(5)^2-1 which would be 25+5-1=29?

Answer 8

correct.

Answer 9

ya, as far as I can tell.
i'm trying to dig up some facts on the differences between the two types

Answer 10

sound good, let me know if there are any changes! :)

Answer 11

thank you also @carrolldy! :)

Answer 12

no problem. im good in math, if you need help hmu! :)

Answer 13

Wow, thanks for offering that! I definitely will :p

Answer 14

@ali1029 @carrolldy
so here is the difference between the direct substitution and sythetic
direct is like this: (what u did)
m(x)=x+x^2-1
m(5)=(5)+(5)^2-1

synthetic is a long process of this:
m(x)=x+x^2-1
5 | 1 1 <-pull down the coefficients in front of the x terms
5 25 <-do the terms x and x^2 so, 5 and 5^2 or 5 and 25
5 25 -1 <-then multiply the 1st row by the 2nd row and add the constants
29 <- then add up all the terms on the 3rd row to get the answer

so... synthetic is a way i think to teach substitution, but clearly the 3 of us are more advanced than this and just do direct substitution

Answer 15

ahhh, so my final answer of 29 is correct? we're so advanced ;)

Answer 16

totes advanced ^_^

Answer 17

hahaha :D