PPPLLLZZZ HHHEEE Joanne earned $57 in tips yesterday. Her earnings were $13 less than 7/8 of Erin's earnings.

1. Write an equation to represent Erin's earnings, x.

2. How much did Erin earn in tips?

9514 1404 393

Step-by-step explanation:

1. I find it convenient to use variable names that remind me what they stand for. Here, we can use "j" to represent Joanne's earnings, and "e" to represent Erin's earnings.

  j = 57 . . . . . Joanne earned $57

  j = (7/8)e -13 . . . . . Joanne's earnings were $13 less than 7/8 of Erin's

Substituting for j, we get one equation for Erin's earnings

  57 = (7/8)e -13

Using 'x' for Erin's earnings, this is ...

  57 = (7/8)x -13

__

2. We can solve the equation as follows:

  70 = 7/8x . . . . . . add 13

  80 = x . . . . . . . . . multiply by 8/7

Erin earned $80 in tips.

Step-by-step explanation:

57 = ⅞x - 13

x= 70(8/7) = $80

just get this app called photo math it should be able to do those

step-by-step explanation:

we have

using a graphing tool

see the attached figure

this is a quadratic equation (vertical parabola) open up

the vertex is a > vertex

the domain of the function is all real > interval (-∞,∞)

the range of the function is the > [-6.125,∞)

the function has two x->   and

the function is increasing over the > (0.25,∞)

the function is decreasing over the > (-∞,0.25)