Simplify the expression. (0.4x10^-6)(0.7x10^-2)

2.8 ·  10^(-9)

Step-by-step explanation:

I'd suggest you do this problem through two separate multiplications:

First, 0.4·0.7 = 0.28, or 2.8 · 10^(-1)

Second, 10^(-6) · 10^(-2) = 10^(-8), and so the final result is

2.8 · 10^(-1) · 10(-8)  =  2.8 ·  10^(-9)

Please note:  negative exponents (such as -9, above) should be enclosed in parentheses for added clarity.

5x + 3y = - 4

step-by-step explanation:

the equation of a line in standard form is

ax + by = c ( a is a positive integer and b, c are integers )

express the line first of all in slope- intercept form

y = mx + c ( m is the slope and c the y-intercept )

to calculate m use the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (7, - 3) and (x₂, y₂ ) = (4, - 8)

m = = -

y = - x + c ← is the partial equation

to find c substitute either of the 2 points into the partial equation

using (4, - 8 ), then

- 8 = - + c ⇒ c = -

y = - x - ← in slope-intercept form

multiply all terms by 3 to eliminate the fractions

3y = - 5x - 4 ( add 5x to both sides )

5x + 3y = - 4 ← in standard form