Write an equation of a line in slope-intercept form for the given conditions.
passes through (4,33) and (1,21)

The desired equation is thus   y = 4x + 17

Step-by-step explanation:

The slope-intercept form of the equation of a straight line is y = mx + b.  There are two values to find:  slope m and y-intercept b.

The line passes through (4, 33).  Thus, 33 = m(4) + b.

The line also passes through (1, 21).  Thus, 21 = m(1) + b, or m = 21 - b.

Thus we have a system of linear equations to solve, and will use the substitution method:

Substitute 21 - b for m in 33 = 4m + b:

33 = 4(21 - b) + b, which, in expanded form, is 33 = 84 - 4b + b, or

                                                                             33 = 84 - 3b, of

                                                                             -51 = -3b.

Thus, b = 17.  Since m = 21 - b, when b = 17, m = 21 - 17 = 4

The desired equation is thus   y = 4x + 17

Of course there are other ways to find this equation.  You could, if you wished, find the slope of the line passing through the given points using the definition of slope, and then find the y-intercept.

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places