Verify the Equality: 4³ - (√49 + √64)·2² vs (4³ - √49) + √64·2²

Question

Indicate whether the equality is true or not.

43(49+64)22=(4349)+6422 4^3-(\sqrt{49}+\sqrt{64})\cdot2^2=(4^3-\sqrt{49})+\sqrt{64}\cdot2^2

Video Solution

Solution Steps

00:00 Is the equation correct?
00:03 Let's start by solving the left side of the exercise
00:10 Let's solve 4 to the power of 3 according to exponent laws
00:17 Let's substitute in our exercise
00:20 Let's find the square root of 49 (7)
00:27 Let's find the square root of 64 (8)
00:30 Let's solve 2 squared according to exponent laws
00:33 Let's substitute in our exercise
00:39 The square root of number A squared equals A
00:42 Let's apply the square root formula for the squared number in our exercise
00:48 Let's solve the parentheses
00:51 Let's continue according to the correct order of operations, so we'll solve multiplication before subtraction
00:54 And we got the solution for the left side of the exercise
01:01 Let's continue solving the right side of the exercise
01:06 Let's substitute the solution for 4 to the power of 3
01:10 Let's substitute the square root of 49
01:14 Let's substitute the square root of 64
01:17 Let's substitute the solution for 2 squared
01:22 Again let's use the square root formula for the squared number
01:29 Let's solve according to the correct order of operations, parentheses first
01:33 And we'll get the solution for the right side of the exercise
01:36 According to our calculation, the equation is not correct
01:39 And this is the solution to our exercise

Step-by-Step Solution

In order to determine if the given equation is correct, we will simplify each of the expressions on its sides separately,

This will be done while following the order of operations which states that exponents come before multiplication and division, which come before addition and subtraction, and that parentheses come before all of these,

A. Let's start with the expression on the left side of the given equation:

43(49+64)22 4^3-(\sqrt{49}+\sqrt{64})\cdot2^2 We'll begin by simplifying the expressions inside the parentheses, this is done by calculating the numerical values of the terms with exponents (while remembering the definition of a root as an exponent, which states that a root is actually an exponent), simultaneously we'll calculate the numerical value of the term with the exponent, which is the multiplier to the right of the parentheses in the second expression from the left and the numerical value of the term with the exponent - the first from the left:

43(49+64)22=64(7+8)4= 4^3-(\sqrt{49}+\sqrt{64})\cdot2^2 =\\ 64-(7+8)\cdot4=\\ We'll continue to perform the addition operation inside the parentheses, in the next step we'll calculate the multiplication by the second term from the left and finally we'll perform the subtraction operation:

64(7+8)4=64154=6460=4 64-(7+8)\cdot4=\\ 64-15\cdot4=\\ 64-60=\\ 4 We have finished simplifying the expression on the left side of the given equation, let's summarize the simplification steps:

43(49+64)22=64(7+8)4=6460=4 4^3-(\sqrt{49}+\sqrt{64})\cdot2^2 =\\ 64-(7+8)\cdot4=\\ 64-60=\\ 4 B. Let's continue with simplifying the expression on the right side of the given equation:

(4349)+6422 (4^3-\sqrt{49})+\sqrt{64}\cdot2^2 Similar to the previous part, we'll start by simplifying the expression in parentheses, this is done by calculating the numerical values of the terms with exponents (and of course this includes the square root), then we'll perform the subtraction operation in the parentheses, simultaneously we'll calculate the numerical values of the root in the second term from the left and of the term with the exponent multiplying it:

(4349)+6422=(647)+84=57+84 (4^3-\sqrt{49})+\sqrt{64}\cdot2^2 =\\ (64-7)+8\cdot4 =\\ 57 +8\cdot4 We'll continue and perform the multiplication in the second term from the left in the next step we'll perform the addition operation:

57+84=57+32=89 57 +8\cdot4 =\\ 57+32=\\ 89 We have finished simplifying the expression on the right side of the given equation, let's summarize the simplification steps:

(4349)+6422=(647)+84=57+32=89 (4^3-\sqrt{49})+\sqrt{64}\cdot2^2 =\\ (64-7)+8\cdot4 =\\ 57+32=\\ 89 Let's now return to the given equation and substitute in its sides the results of simplifying the expressions detailed in A and B:

43(49+64)22=(4349)+64224=89 4^3-(\sqrt{49}+\sqrt{64})\cdot2^2=(4^3-\sqrt{49})+\sqrt{64}\cdot2^2 \\ \downarrow\\ 4=89 Obviously this equation does not hold true, meaning - we got a false statement,

Therefore the correct answer is answer B.

Answer

Not true