Please answer all of these questions fastly quickly URGENTLY.
Answers
Answers-
7. First adding
4a + 2b + 3c + 2a - 4b + 5c
=(4a+2a) + (2b-4b) + ( 3c +5c)
=6a - 2b + 8c
2nd subtracting
6a -2b+8c - (6a +7b-2c)
=6a - 2b + 8c - 6a - 7b +2c
= -9b+10c
8. one no + another no. = sum
= sum - one no = another no.
= (x² + 4xy - 2y²) - (3x² - 7xy +5y²)
= x² + 4xy -2y² - 3x² +7xy -5y²
=x² -3x² + 4xy +7xy -2y² -5y²
= -2x² +11xy -7y²
9 one no. - another no. = difference
∴ difference - one no. = another no.
= (-4x² -2xy - y²) - (3x² -7xy +5y²)
=-4x² - 2xy - y² - 3x² + 7xy - 5y²
= -4x² -3x² -2xy +7xy -y² -5y²
= -7x² +5xy -6y²
10. A = 2x² -3x + 1
B = 4x² +2x -7
C = 3x² - 6x + 2
∴ A + B - C = (2x² - 3x +1 ) + (4x² + 2x -7) -(3x² - 6x + 2)
=2x² - 3x +1 + 4x² + 2x - 7 -3x² + 6x - 2
= 2x² + 4x² - 3x² -3x +2x + 6x + 1 -7 -2
=3x² +5x -8
11. x = 2 ; y = 3 ; z =-4
i) 4xy² - 15x²y + zx
= 4(2)(3)² - 15(2)²(3) + (-4)(2)
=4(2)(9) - 15(4)(3) + ( -8)
= 72 - 180 -8
= -116
ii) x³ + y³ + z³ + 3xyz
= (2)³ + (3)³ + (-4)³ + 3(2)(3)(-4)
=8 + 27 - 64 -72
= -101
12. a=3 ; b = 2 ; c=5
i) a² - 3b² + ac
= (3)² - 3(2)² + (3)(5)
= 9 - 12 +15
=12
ii) 4a³ + 2b³ - 3c³
=4(3)³ + 2(2)³ - 3(5)³
=4(27) + 2(8) - 3(125)
=108 + 16 - 375
= -251
13. x = 1; y= -2 ; z = 3
i) x³ + y³ + z³ - 3xyz
= (1)³ + (-2)³ + (3)³ - 3(1)(-2)(3)
= 1 - 8 + 27 +18
=38
ii)2xy^4 - 14x²y + 4z
= 2(1)(-2)^4 - 14(1)²( -2) + 4(3)
=2(1)(16) - 14(1)(-2) + 12
=32 + 28 +12
=72