Solving a system of linear equations y=-x-4 and y=3/5x +4

(-5, 1)

Step-by-step explanation:

Using substitution, you can solve the system of equations to first solve for one variable and then solve for the other.  Given the following two equations:

y = -x - 4 and y = 3/5x + 4, since both equations are equal to 'y', you can set them equal to each other and solve for 'x':

-x - 4 = 3/5 x + 4

Add 'x' to both sides: -x - 4 + x = 3/5x + 4 + x or -4 = 8/5x + 4

Subtract 4 from both sides: -4 - 4 = 8/5x + 4 - 4 or -8 = 8/5x

Multiply both sides by reciprocal of 8/5 (5/8):  (5/8)(-8) = 8/5x(5/8)

Simplify:  -5 = x

Solve for y:  y = -(-5) - 4 or y = 5 - 4 = 1

(-5, 1)

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