Algebraic Expre...

If $$P=3x-4y-8z$$, $$Q=-10y+7x+11z$$ and $$R=19z-6y+4x$$, then $$P-Q+R$$ is equal to

What is the simplified result of following the steps in order?
$$(1)$$ add $$5y$$ to $$2x$$
$$(2)$$ multiply the sum by $$3$$
$$(3)$$ subtract x$$+$$y from the product

The sum of three expressions is $${ x }^{ 2 }+{ y }^{ 2 }+{ z }^{ 2 }$$. If two of them are $$4{ x }^{ 2 }-5{ y }^{ 2 }+3{ z }^{ 2 }$$ and $$-3{ x }^{ 2 }+4{ y }^{ 2 }+2{ z }^{ 2 }$$, the third expression is

$$\left( 4p{ x }^{ 2 }+5{ q }^{ 2 }y-9rz \right) -\left( -3{ q }^{ 2 }y+7p{ x }^{ 2 }-rz \right) =$$

The sum of three expressions is $$x^{2}+y^{2}+z^{2}.$$ If two of them are $$4x^{2}-5y^{2}+z^{2}$$ and $$-3x^{2}+4y^{2}+2z^{2}$$, find the third expression.

Subtract $$2x^{3}-4x^{2}+3x+5$$ from $$4x^{2}+x^{2}+x+6$$, then the resultant value is 

Add: $$2u+3v,\,\,-2v+3w,\,\,3u-v+2w$$

Simplify: $$a-[b-\{c-(a-b-c)\}-c]+a$$

The sum of $$(6a+4b-c+3), (2b-3c+4), (11b-7a+2c-1)$$ and $$(2c-5a-6)$$ is

The sum of $${x}^{4}-xy+2{y}^{2}$$ and $$-{x}^{4}+xy+2{y}^{2}$$ is