Subtract and simplify (-y^2-3y--7y+4)

[ Answer ]

[ Explanation ]

(-y - 3y - 5) - (3y - 7y + 4)

[Remove Parenthesis]

-y - 3y - 5 - (-3y - 7y + 4)

-(-3y - 7y + 4): 3y + 7y - 4

-y - 3y - 5 + 3y + 7y - 4

[Simplify] -y - 3y - 5 + 3y + 7y - 4: 2y + 4y - 9

= 2y + 4y - 9

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form

according to the triangle sum theorem, all the angles in a triangle must add up to 180 degrees. if we know one angle is already 90, we do 180-90=90. the other 2 angles must add up to 90, exactly.

step-by-step explanation: