By how many times does the sample size have to be increased to decrease the margin of error by a factor of 1/2

Rewrite the following quadratic functions in intercept or factored form. show your work. y = 5x^2 + 10x

Eden has a part time job. she is paid ? 7.20 an hour the week she worked 18 and a half hours how much is she paid

Find the value of the variable and the length of each chord for #5 and #6.