Question

If 2a - 7b = 10 and 2a + 7 = 2, what is the value of 4a^2 - 49b^2?​

Answer 1

Ответ:

20

Пошаговое объяснение:

2a - 7b = 10

2a + 7b = 2

4a^2 - 49b^2=(2a - 7b)*(2a + 7b)=10*2=20

Answer 2

First, let's solve the given equations: 2a - 7b = 10 2a + 7 = 2

From the second equation, we can solve for a: 2a = 2 - 7 2a = -5 a = -5/2

Now that we have the value of a, we can use it to solve for b in the first equation: 2(-5/2) - 7b = 10 -5 - 7b = 10 -7b = 10 + 5 -7b = 15 b = -15/7

Now that we have the values of a and b, we can find the value of 4a^2 - 49b^2: 4a^2 - 49b^2 4(-5/2)^2 - 49(-15/7)^2 4(25/4) - 49(225/49) 25 - 225 -200

So, the value of 4a^2 - 49b^2 is -200.