She earns 20 dollars as a carpenter and 25 dollars as a blacksmith
b+c=30 hours since she works 30 hours a week
25b+20c=690 since she earns 690 dollar totally and earns 25 dollars an hour as a blacksmith and 20 dollars an hour as a carpenter
lets multiply b+c=30 by -20
-20b-20c=-600
if we substract that from
25b+20c=690
5b=90
b=18 she worked as a blacksmith for 18 hours
Answer and Step-by-step explanation: <u>Standard</u> <u>form</u> of a quadratic equation is expressed as: y=ax²+bx+c, while <u>vertex</u> <u>form</u> is written as:
y=a(x-h)²+k.
The similarities between standard and vertex forms is that they show if the graph of the equation has a <u>minimum</u> (when a>0) or <u>maximum</u> (a<0) and it's easier to determine the y-intercept: for standard, the value of c is the intercept; for vertex, the value k is the intercept.
The advantage of standard form is that you can determine the product and sum of the equation's roots, which is a method to determine them.
The advantages of vertex form are: easier to find the vertex of the graph, which is the pair (h,k) and the axis of symmetry, which is the value of h.
Answer:
Step-by-step explanation:
