The sum of two numbers (x + y) is 8 (=8).
Their product (x * y) is 15 (=15).
x + y = 8
x * y = 15
First, we know that the two number must be positive and under 8, as the product is positive.
Let's list out some numbers that are from 1 to 8 that sum up to 8;
1 + 7
2 + 6
3 + 5
4 + 4
Now, we need to multiply the two numbers that add up to 8, and see which makes a product of 15.
1 * 7 = 7, this does not work.
2 * 6 = 12, this does not work.
3 * 5 = 15, this works!
4 * 4 = 16, this does not work.
Since we are looking for the larger number in our pairs, let's pick the largest one out of the correct pair, which is 5.
The largest number is 5.
I hope this helps!
15, -7 x=15 y=-7
x+y=8, we'll come back to this
x-y=22, move y to the other side, x=y+22
now insert the value of x =(y+22) to the other equation like so, (y+22)+y=8, simplify
2y+22=8 2y=(-14), y=(-7)
Insert the value of y into the first equation again like so, x+(-7)=8, simplify
i will say 15 and -7
15+-7=8 and 15--7=22
15+-7 so take the negative and take out that mush of the big number
15--7= the subtracting beside a negative makes it changes to positive and addition so 15+7=22
From their product, x(8 - x) = 80 .
When you massage and manipulate this equation into the standard
quadratic form, you have
x² - 8x + 80 = 0 .
Applying the quadratic formula to tease out the solutions of this equation,
we find that they are
x = 4 + 64 i
x = 4 - 64 i
the 3rd option is right
the function makes a strait line horizontally with no x intercept but a y intercept at 9.