Answer:
15 equations
Step-by-step explanation:
Let
Number of equations in the homework = x
There is only a one-word problem
y = amount of time used to solve the word problem
She took 3 minutes to solve each equation, then 7 minutes to solve the word problem if it took her 52 minutes total,
Total = 3x + y
52 = 3x + 7
Subtract 7 from both sides
52 - 7 = 3x + 7 - 7
45 = 3x
Divide both sides by 3
x = 45 / 3
= 15
x = 15 equations
Therefore, she solved 15 equations
Answer:
for 7% , $8,000
for 8.5%, $4,000
Step-by-step explanation:
Key amount at 7% be x and amount at 8.5% be y
Mathematically;
x + y = 12,000 ••••••(i)
Let’s now work
with the interest;
7% of x + 8.5% of y = 900 ••••••(ii)
0.07x + 0.085y = 900
So we have two equations to solve simultaneously
From 1, x = 12,000-y
Substitute this into ii
0.07(12000-y) + 0.085y = 900
840-0.07y + 0.085y = 900
0.015y = 900-840
0.015y = 60
y = 60/0.015
y = 4000
x = 12000-4000
x = $8,000
Can you send a picture, because this doesn’t make it clear what the options are/what to do
The steps involving properties of equality are shown in painful detail.
For Step 4, you add 7 to both sides of the equation (with the goal of cancelling the -7 on the left). So you have
6x -7 +7 = 12 +7 . . . . . . . showing 7 added to both sides
In the next step, this is simplified to the way you might have written it to start with:
6x = 19
There should be no confusion in any of this. All solutions of all equations make use of the properties of equality like this. Addition is used to cancel subtraction, division is used to cancel multiplication. (Root-taking cancels powers, and vice-versa; inverse trig functions cancel trig functions; and so on.)