Answer:
See solutions below
Step-by-step explanation:
1) Total amount of gallons = 14 gallons
If she uses up 0.75 gallons of gas each hour then;
1 hour = 0.75gallons
after driving 6 hours, amount of gallons used will be;
6 hours = x
Divide both expressions
1/6 = 0.75/x
x = 6 * 0.75
x = 4.5gallons
Amount of gas left = 14 - 4.5 = 9.5 gallons of gas
Hence 9.5 gallons of gas will be left after 6 hrs
Similarly;
1 hour = 0.75gallons
after driving t hours, amount of gallons used will be;
t hours = x
x = 0.75t
Amount of gas left after t hours = (14 - 0.75t) gallons of gas
2) We are to find the sum of -8x^2+3 and -9x^2+3x-3
-8x^2+3 + (-9x^2+3x-3)
= 8x^2+3 -9x^2+3x-3
Collect like terms
= 8x^2 -9x^2+3x + 3-3
= -x^2 + 3x
Hence the sum is -x²+3x
3) Expressing in standard form;
(-3x-5)(-x^2+x-5)
Expand
= 3x³-3x²+15x+5x²-5x+25
Collect like terms
= 3x³-3x²+5x²+15x-5x+25
= 3x³+2x² + 10x + 25
Hence the product in polynomial form is 3x³+2x² + 10x + 25
