A) Substitution
substitute y = 5x-2 for y in the first equation and solve for x:
5x-2 = 7x-8 subtract 7x from both sides
-2x-2 = -8 now add 2 to both sides
-2x = -8 + 2 simplify
-2x = -6 divide both sides by -2
x=3
Now substitute x with 3 in either equation
y=5x-2 =5*3-2 =13
(3,13)
B) (3,13) is the point where the two lines intersect
y=mx+b is the equation of a line
There's 6 hours and twenty minutes between 8:20 and 2:40, which means you would divide 335 mi by 6.2 hrs. Thats gets you the answer of 54 mph (54.03 to be exact.) Hope that helps!
Okay so you start with 1/3. Fractions are just a fancy way of saying (in this case) 1 divided by 3. And if you do that you'll get .3333. After that to make it a percent you just move the decimal spot in front of the 3 over two places, getting 33.33%. With mixed numbers it's just one more step. So in this case 2 1/5 you would have to make it a normal fraction first so I got 11/5ths and here's how I got it. 2 1/5. Multiply the denominator (5) with 2. You get 10. Then add the numerator (1) to get 11. Tack on the 5 and you get 11/5. To make this a percent just do the same thing as the normal fractions... 11 divided by 5 to get 2.2. Move the decimal two places to the right to get 220%. Try the rest on your own and if you get confused ask... :)
15x^2 + 12x +10x + 8= 0 reduced 15x^2 +22x+ 8 = 0
Recall that the quadratic formula is
x=(-b+/-sqrt(b^2-4ac)/2a
So the formula cannot be used whenever a=0, in other words, the coefficient of the x^2 term is zero. All other situations do not render the formula inapplicable.