Find the x-and y-intercepts of the graph of the equation algebraically. y=-5x+6

A hybrid course is one that contains both online and classroom instruction. In a study performed at Middle Georgia State University, a software package was used as the main souce of instruction in a hybrid college algebra course. The software tracked the number of hours it took for each student to meet the objectives of the course. In a sample of 45 students, the mean number of hours was 80.5, with a standard deviation of 51.2.
a. Construct a 95% confidence interval for the mean number of hours it takes for a student to meet the course objectives.

The tensor product of two vector spaces U and V is defined as the dual of the vector space of all the bilinear forms on the direct sum of U and V. Is there a generalised form of this for the direct sums of more than two vector spaces? Is there a relation between the space of all multilinear forms on the direct sum of $V_1$,$V_2$,$V_3$,...,$V_k$ with their tensor product.
Please explain without invoking other algebraic objects such as modules,rings etc and by using the concepts regarding vector spaces only (as the book assumes no such background either, it is unlikely that any reader of that book will benefit from such an exposition). Everywhere I searched, I found the explanation in terms of those concepts only and being unfamiliar to those I couldn't get them at all. Thanks in advance.

A multiple regression equation to predict a student's score in College Algebra $(\hat{y})$ based on their high school GPA ($x_1{x}_1$), their high school Algebra II grade ($x_2{x}_2$), and their placement test score ($x_3{x}_3$) is given by the equation below.
$\hat{y}=-9+5x_1{x}_1+6x_2{x}_2+0.3x_3{x}_3$
a) According to this equation, what is the predicted value of the student's College Algebra score if their high school GPA was a 3.9, their high school Algebra II grade was a 2 and their placement test score was a 40? Round to 1 decimal place.
b) According to this equation, what does the student's placement test score need to be if their high school GPA was a 3.9, their high school Algebra II grade was a 2, and their predicted College Algebra score was a 67? Round to 1 decimal place.

To calculate: The probability that the selected student received an "A" in the course.
Given Information:
A table depicting the grade distribution for a college algebra class based on age and grade.

To calculate: The probability that the selected student of 37-46 age group has received an "A" in the course.
Given Information:
A table depicting the grade distribution for a college algebra class based on age and grade.

Pure acid is to be added to a 20% acid solution to obtain 28 L of a 40% acid solution. What amounts of each should be used?

Is there a genuinely respectable published expository account of what power series are used for, of which a substantial portion would be comprehensible to those first learning of power series in a first-year calculus course?
(I think it's a flaw in the way mathematics is conventionally taught that one first learns answers to questions like this only by taking a later course for which the one introducing the concept is a prerequisite, and one has no prior notice of which course that might be. And in the case of power series, there are many such courses, but still very few compared to the number of courses a student might later take, so the situation is worse.)