Question 79978
1. Simplify and evaluate:
(x7y-4z0/5-2x3y-8z-9)2
:
This is so ambiguous it could be:
:
{{{(((x^7*y-4z^0))/((5-2x^3y-8z-9)))^2}}}
:
you can't do very much with this so maybe you mean:
:
{{{(((x^7*y^-4*z^0))/((5^-2*x^3*y^-8*z^-9)))^2}}}
:
any number ^0 is 1 so we can get rid of z in the numerator
:
{{{(((x^7*y^-4))/((5^-2*x^3*y^-8*z-9)))^2}}}
:
Change the exponents signs when you move terms from the denominator to the numerator
{{{(5^2*x^7*x^-3*y^-4*y^8*z^9)^2}}}
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Combine like terms, add the exponents
{{{(25*x^4*y^4*z^9)^2}}}
:
Square each term, multiply each exponent by 2
{{{625*x^8*y^8*z^18}}}
:
It's simplified but can't evaluate because we don't know the value of the variables.
:


2. Convert to scientific notation (here you may use x as multiplication):
0.00452
:
Move the decimal point to the right between the 1st and 2nd significant digits;
"tenths, hundredths, thousands" which would be {{{10^-3}}}
WE then have {{{4.52*10^-3}}}




3. For f(x) = 5x – 4, find f(-1). 
:
f(-1) just means you substitute -1 for x evaluate:
f(-1) = 5(-1) - 4
f(-1) = -5 -4
f(-1) = 9
:
When the problems are ambiguous, it discourages tutors from choosing to help you.  When in doubt, use brackets.