Answer:
[tex]3m^2+5n^2+8mn[/tex]
[tex]x^2-11x+17[/tex];0
Step-by-step explanation:
We have been given [tex]m^2+3mn−n^2 [/tex] and [tex]4m^2+5mn+6n^2[/tex]
for (1) we will subtract [tex]4m^2+5mn+6n^2[/tex] from [tex]m^2+3mn−n^2 [/tex] that is:
[tex]4m^2+5mn+6n^2-m^2+3mn-n^2[/tex]
Now, simplify the like terms we get:
[tex]4m^2-m^2+6n^2-n^2+5mn+3mn[/tex]
After simplification we get:
[tex]3m^2+5n^2+8mn[/tex]
Hence, [tex]3m^2+5n^2+8mn[/tex] is the required result.
(2) Now, we need to find how much less than [tex]3x^2-7x+9[/tex] is [tex]2x^2+4x-8[/tex]
Subtract [tex]3x^2-7x+9[/tex] from [tex]2x^2+4x-8[/tex] we get:
[tex]3x^2-7x+9-2x^2-4x+8[/tex]
After simplifying like terms
[tex]x^2-11x+17[/tex]
When x=2 the the above expression becomes:
[tex](2)^2-11(2)+17[/tex]
[tex]4-22+17=0[/tex]
