Answer:

Step-by-step explanation:
You could either do what I did in the above answer, or you could do this:

It does not matter how you write it, as long as you understand the concept!
I am joyous to assist you anytime.
The sides of the triangle are 3x, 4x and 5x
3x + 4x + 5x = 90
12x = 90
x = 90/12
x = 7.5
first side = 3x = 3 * 7.5 = 22.5 cm
second side = 4x = 4 * 7.5 = 30 cm
third side = 5x = 5*7.5 = 37.5 cm
Answer:
x=9
Step-by-step explanation:
2x+12=5x-15
3x=27
x=9
Answer:
Opt. 1 -3 ≤ x ≤ 3
Step-by-step explanation:
Inequalities are regions, the attached picture shows us a region located between -3 and 3, the dots used are solid, this means that the value '3' is include in the region.
Hence the variable is narrowed to -3 and 3.
Answer:
C
Step-by-step explanation:
A closed circle means inclusive, and -2 is included in values that would make the equation true. Then you just have to test another number greater than and less than -2 to see which way the arrow should point.
-3(-3) + 1 < 7
9 + 1 < 7
10 < 7 FALSE
-3(0) + 1 < 7
1 < 7 TRUE
All values (including -2) will make this equation true