Answer: Answers are in the steps read carefully!
Step-by-step explanation:
A) 3x^2 - 7x + 2 To factor this polynomial, you have to find two numbers that their product is 6 and their sum is -7. The numbers -1 and -6 works out because -6 times -1 is 6 and -6 plus -1 is -7.
Now rewrite the polynomial as
3x^2 - 1x - 6x + 2 Now group it
(3x^2 - 1x) (-6x+2) Factor it by groups
x (3x -1) -2(3x -1) Now factor out 3x-1
(3x -1) (x-2) Done!
B) 2x^2 - x -3 Now the same way.You will have two numbers that their product is -6 and their sum is -1. You may be wondering how I get -6 .I get -6 by multiply the leading coefficient 2 by the constant -3. The numbers -3 and 2 works out. Because -3 times 2 is -6 and -3 plus 2 is -1.
Rewrite the polynomial as
2x^2 +2x - 3x -3 GRoup them and factor them
(2x^2 + 2x) (-3x-3)
2x(x+1) -3(x+1) Factor out x+1
(x+1) (2x -3) Done!
C) 3x^2 - 16x - 12 Find two numbers that their product is -36 and their sum is -12. The numbers -18 and 2 works out because -18 times 2 is -36 and -18 plus 2 is -16.
Rewrite the polynomial
3x^2 +2x -18x - 12 GRoup them
(3x^2 + 2x) (-18x - 12) Factor them
x (3x +2) -6(3x +2) Factor out 3x+2
(3x+2) (x -6) Done !
This is how you work it out:
u + xy
Plug in your numbers that you know:
20 + 9 * 8
20 + 72
92
The cost is £79.76. Since the car covers 560 miles and 34.5 miles is travelled by one gallon. So, dividing 560 by 34.5 we get 16.23. Since 1 gallon is 4.55 litres, 16.23 gallons is 73.8465. Now the cost of petrol is £1.08 per litre. So, multiplying 73.8465 by £1.08 we have £79.76
