How do you solve 7(4x +9)-13=-877(4x+9)13=87?

3 Answers
May 7, 2017

-4.894.89 or -137/2813728

Explanation:

Start with the easiest step, which is adding 1313 to both left hand side and right hand side.

7(4x+9) cancel(-13 + 13) = -87 + 13
7(4x+9) = -74

Next, divide both LHS and RHS by 7

(cancel7(4x+9))/cancel7 = -74/7
4x+9 = -74/7

Subtracting LHS and RHS by 9,

4x cancel(+9-9) = (-74/7)-9
4x = -137/7

Dividing LHS and RHS by 4,

cancel4x/cancel4 = -137/28
x = -137/28 or -4.89

See below

Explanation:

First of all you will have to expand your bracket and this is how you will get a normal solving equation and be able to find what x is.
To expand the bracket you have to know that you need to multiply everything inside the bracket by the outside:
7(4x+9)-13=-87
28x+63-13=-87 Expand the bracket

28x+63=-74 Get rid of -13 by ading it to both sides because you have to always do the same to both sides of the equal sign. Therefore if you have -13 you +13.
28x=-137 You then subtract 63 because you need x on its own. To do this you look at the sign before the number 63, in this case you have +63 which means you have to subtract 63 and you get that 28x=-137 and you divide by how many x you have to find what 1 x is
x=-4.892857143
or round it -4.9
I hope this helps you!

May 9, 2017

color(blue)(x=4.893 to the nearest 3 decimal places

Explanation:

7(4x+9)-13=-87

:.28x+63-13=-87

:.28x=-87-63+13

:.28x=-150+13

:.28x=-137

:.x=-137/28

:.color(blue)(x=4.893 to the nearest 3 decimal places