<span>B. Carbon dioxide gas in air </span>
y = -2x + 3....slope = -2, y int = 3
2x + 4y = 8
4y = -2x + 8
y = -1/2x + 2....slope is -1/2, y int is 2
this is graph C
Rebecca has 21 math problems
She has solved none....
2-7=-5
You cannot solve negative five problems
Answer: 0
Lets call those two unknown numbers a, b and write the info in the problem as equations:
a*b = 30
a + b = 40
lets solve for a in the second equation and substitute in the first:
<span>a + b = 40
</span>a = 40 - b
therefore:
<span>a*b = 30
</span>(40 - b)b = 30
40b - b^2 = 30
b^2 - 40b + 30 = 0
if we apply the general quadratic equation to solve we have:
b = (40 +- √(1600 - 120))/2
b = (40 +- √(1480<span>))/2
</span>b = (40 +- 38.47)/2
There are two solutions:
<span>b1 = (40 + 38.47)/2
</span><span>b1 = 39.24
b2 = (40 - 38.47)/2
</span>b2 = 0.765
lets use the second solution <span>b2 = 0.765, and substitute in the first equation to find a:
</span><span>a*b = 30
</span>a*0.765 = 30
a = 30/0.765
a = 39.216
so the numbers are 39.216 and 0.765