Question #bad20

1 Answer
Nov 13, 2017

Answer 1:
x(xy + 7)^3x(xy+7)3

Answer 2:
xz^5xz5

Answer 3:
yx + xyx+x or x + x(y+4)x+x(y+4) or x + 2xy^3x+2xy3

Answer 4:
x + (y+2)zx+(y+2)z

Explanation:

Answer 1:
x(xy + 7)^3x(xy+7)3

The question asks for a product of xx and a factor that depends on xx. Therefore you know that:

  • You need to have multiplication of xx and some other factor.
  • Your other factor should change as you change xx.

Hence, x(xy + 7)^3x(xy+7)3 is your best bet, as you have multiplication, and your other factor - (xy + 7)^3(xy+7)3 - changes with xx.

Answer 2:
xz^5xz5

Again, you are asked for a product, but this time your factor does not depend on xx. Therefore, you know:

  • You must have multiplication of xx and some other factor.
  • Your other factor should not change as you change xx.

So, xz^5xz5 is your best answer. You have multiplication, but zz does not change with xx.

Answer 3:
yx + xyx+x or x + x(y+4)x+x(y+4) or x + 2xy^3x+2xy3

Here, you're asked for a sum of two terms: xx, and some multiple of xx. So, you know that:

  • You have addition of xx and some other term.
  • Your other term must be xx multiplied by some factor (in terms of any other variable).

You have three answers that fulfill this criteria (listed above): all of them have xx added to xx times some factor (in terms of yy).

Answer 4:
x + (y+2)zx+(y+2)z

Here, you're again asked for a sum, but this time your other term must not depend on xx. Therefore, you know:

  • You have addition of xx and some other term.
  • Your other term must not have xx in it.

x + (y+2)zx+(y+2)z is your best choice here. Note that you have only yy and zz as variables in your 2nd term, and neither of those depend on xx, making this your best answer.

Hope that helps :)