1. Which of the following is a linear equation? a) 12x + y = 19.b) x = −y + 2.c) sinx + 9y = −4.d) 2x − 3y10 = −3x + 4y5.e) x2 − y2 = 1(f)√x = y.2. Give an example of the following of a linear combination int, u, v, w.3. Consider the set of planes: 3x + 4y − z = 8, x − y − 2z = 0.In order to find the point(s) of intersection of the two planes, we would need to solve a) linear combinationin x, y, z. b) linear equationin x, y, z. c) linear systeminx, y, z.4. Is it possible for a linear system to have exactly two solutions? Why or why not?5. Consider the linear system: x+ 2y − 2z = 33x − y + z = 1 − x + 5y − 5z = 5Which of the following ordered triples is a solution to the system? a) (57,87,1).b) (57,87,0).c) (5,8,1).d) (57,227,2).6. Express the following notation in words:m, n∈R7. Consider the following non-linear system: 11et − 2√u = 35et + √u = 9 (1)Although this system is non-linear, it is possible find a change of variables x, y so that (1) becomes linear system when it is expressed in terms of x, y. Identify the change of variablesx, y.