Solve the simultaneous equations
2x + y = 1 and x2 + y2 + xy = 7.

Find the gradient of f(x, y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).

If chord ab is congruent to chord cd, then what must be true about ef and eg?

Robert plans to make a box-and-whisker plot of the following set of data. 27, 14, 46, 38, 32, 18, 21 find the lower quartile, the median, and the upper quartile of the set? lower quartile: 19.5; median: 29.5; upper quartile: 42 lower quartile: 14; median: 27; upper quartile: 46 lower quartile: 18; median: 27; upper quartile: 38 lower quartile: 16; median: 29.5; upper quartile: 42