Answer:
Step-by-step explanation:
xy = 42
x+y = - 2 Substitute into the top equation
y = -2 - x Put in for y
x(-2 - x) = 42 Remove the brackets
-2x - x^2 = 42 Subtract 42 from both sides.
-2x - x^2 - 42 = 0 Put in the more normal order.
-x^2 - 2x - 42 = 0 Multiply by -1
x^2 + 2x + 42 = 0
This cannot be factored. It gives complex roots as it is written. I will give you the answer but I kind of doubt the question is correct.
x1 = - 1 + 6.40i
x2 = -1 - 6.40i
Leave a comment if you have a correction.
Answer:
240
Step-by-step explanation:
The <em><u>correct answer</u></em> is:
7.8 × 10⁷
Explanation:
To write a number in scientific notation, we want the decimal behind the first non-zero digit in the number. The first non-zero digit in 78 is 7; this means we want 7.8. In order to have the decimal point behind the 7, we need to move the decimal 7 places. This is the exponent of 10 in our scientific notation, which gives us
7.8 × 10⁷

This gives us

We can take 4x from each term to get

as your answer