Answer:
-4a + 7a = + 3a
But you don't actually need a pkus sign 3a is fine too. You are basically sum - 4 and 7. Let me know if you still confused.
Answer:
(5 + 3i)(5 − 3i) = 34
Step-by-step explanation:
The multiplication of two identical binomials who have different symbol, can be solved using the factoring case of a difference of squares:

So, in this case:


Remember that 
So: 
We replace on the polynomial:

X^2-7x+38=5x+3
x^2-7x+38-5x-3=5x+3-5x-3
x^2-12x+35=0
Factoring:
(x-5)(x-7)=0
Two solutions:
x-5=0→x-5+5=0+5→x=5
x-7=0→x-7+7=0+7→x=7
Answer: x=5 and x=7
Answer: Options B. 7 and D. 5
13
Explanation: a^2 + b^2 = c^2
12^2 + 5^2 = c^2
144 + 25 = c^2
/169 = c
c = 13
Given the table below which lists the masses and volumes of several pieces of the same type of metal.<span>
From the table the ratio of the mass to the volume of the metal of mass 34.932 is 34.932 / 4.1 = 8.52
</span><span>the ratio of the mass to the volume of the metal of mass 47.712 is 47.712 / 5.6 = 8.52
</span><span>the ratio of the mass to the volume of the metal of mass 61.344 is 61.344 / 7.2 = 8.52
</span><span><span>the ratio of the mass to the volume of the metal of mass 99.684 is 99.684 / 11.7 = 8.52
</span>MASS (grams) VOLUME (cubic cm.)
34.932 4.1
47.712 5.6
61.344 7.2
99.684 11.7</span>
Since the ratio of the various masses to the volume of the metals is the same, so there is a relationship between the mass and the volume of the piece of metal.
If the volume of a piece of metal is 15.3 cubic cm, then the mass of the metal is given by 15.3 * 8.52 = 130.356 grams.