AboutJosh Expertise When I work through problems, I emphasize principles and key ideas which I believe are worth noting. I will try to answer questions in the following areas, but not at the advanced level. Algebra. Sequences & Series. Trigonometry. Functions & Graphs. Coordinate Geometry. Quadratic Polynomials. Exponentials & Logarithms. Basic Calculus. Probability, Permutations and Combinations. Mathematical Induction. Complex numbers. Physics problems.
Experience
Experience: I have worked as a teaching assistant in college. My hope is that more people will share knowledge without boundary, give help without seeking recognition or monetary rewards.
Supplementary Website: See a selection of past questions in my maths repository under "Question Archive"
Education Credentials: Bachelor degree in Engineering Science."Everyone struggles with something."
As a general rule, always simplify any expression inside the parenthesis first if at all possible. Then, do all the multiplications and divisions, from left to right; followed by additions and subtractions.
Here, we note that -6x-7(4+3x) is a shorthand way of writing -6x-7*(4+3x). We deal with the expansion of 7(4+3x) first, since multiplication takes precedance over addition and subtraction. We associate 7 with (4+3x) and multiply them together. This gives 7*4+7*3x = 28 +21x.
The whole thing "-6x-7(4+3x)" then becomes
-6x -(28+21x) (we have replaced 7(4+3x) with 28+21x)
= -6x -28 -21x (note)
= -6x-21x -28
=-27x -28
note: in this line, we gather the two terms that contain "x" and do the required subtraction.
