2х + y = 20
6x — 5y = 12
How do i solve this? This is Systems of equations: Substitution

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)

Multiply and simplify. 2x2y3z2 · 4xy4x2 how to do?

State if it is acute obtuse or right