Solve the equation:8^4-x=2^1-y and 3^x+1=9^-y​

4+6x-3x^3 in standard form with explanations because i don’t understand

The long jump record, in feet, at a particular school can be modeled by f(x) = 19.6 + 2.5ln(x + 1) where x is the number of years since records began to be kept at the school. what is the record for the long jump 11 years after record started being kept? round your answer to the nearest tenth.

(a) calculate the molarity of a solution that contains 0.0345 mol nh4cl in 400 ml of solution. (b) how many moles of hno3 are present in 35.0 ml of a 2.20 m solution of nitric acid? (c) how many milliliters of 1.50 m koh solution are needed to supply 0.125 mil of koh ?