We know that : (a - b)(a + b) = a² - b²
We know that : 1 - sin²x = cos²x
We know that : sec²x = 1 + tan²x
Answer:
7.2*10^3.
7,200 in scientific notation, is 7.2*10^3
Step-by-step explanation:
You want to set one of the equations equal to either x or y. For this, I put x+y=-2 equal to y which would be y=-x-2. Then you plug this in to the other equation for y. This would give you 5x+2(-x-2)=2. When you factor the two into the parenthesis, combine like terms, and keep the x values on ones side and the other numbers on the other side, you get 3x=6