Page:Elementary algebra (1896).djvu/39

21 Rh Ex. 1. From 5 x^2 + xy - 3 y^2 take 2 x^ + 8 x - 7 y^2. 5x^2 + xy - 3 y^2 2 x^2 + 8 xy - 7 y^2 3 x^2- 7 xy + 4 y^2.

Ex. 2. Subtract 3 x2 - 2 x from 1 - x^3.

Terms containing different powers of the same letter being unlike must stand in different columns. The rearrangement of terms in the first line is not necessary, but it is convenient, because it gives the result of subtraction in descending powers of x.

-x3 + 1 3x2 - 2 x -x3- 3x^2 + 2x + 1

ExAMPLES III. c.

Subtract

1. 4 a - 3b + c from 2a-3b - c. 2. a - 3b + 5 c from 4 a - 8b + c. 3. 2 x - 8 y + 2 from 15 x + 10 y - 18 z. 4. 15 a - 27b + 8 c from 10 a + 3b + 4 c. 5. - 10 x - 14 y + 15 z from x - y - z. 6. - 11 ab + 6 cd from - 10b + ab - 4 cd. 7. 4a - 3b + 15 c from 25 a - 16b - 18 c. 8. - 16 x - 18 y - 15 z from -5x + 8y+7z. 9. ab + cd - ac - bd from a + cd + c + bd. 10. - ab -- cd - ac + bd from ab - cd + ac - bd.

From

11. 3 ab + 5 cd - 4 ac - 6 bd take 3 ab + 6 cd - 3 ac - 5 bd. 12. yz - xz + xy take - xy + yz - xz. 13. - 2 x3 - x2 - 3 x + 2 take x^3 - x + 1. 14. - 8 x2y + 15 xy2 + 10 xyz take 4 x2y - 6 xy^2 - 5 xyz. 15. ^a-b + c take a + ^ b - J c. 16. x -- y - z take x -  y - i 0. 17. - a - 3 b take f a + i b - J c. 18. x - y + z take - Jx + y - jL^. 19. - x - y - z take | x - y - JJ- z 20. -x + y- take x-y-.