Answer:
Q 19) x = 4; y = 8.
Q 20) x = 0 ; y = 0.
Q 21) x = -1; y = -5.
Step-by-step explanation:
Q 19)
y = 3x - 4 (Equation 1)
x - 4y = -28 (Equation 2)
Put Equation 2 in Equation 1:
x - 4(3x - 4) = -28.
x - 12x + 16 = -28
-11x = -44.
x = -44/-11.
x = 4.
Put x = 4 in Equation 1:
y = 3(4) - 4.
y = 12 - 4.
y = 8.
Q 20)
2x - 3y = 13x - 4y (Equation 1)
-3x - 2y = 0 (Equation 2).
From Equation 2:
-2y = 3x.
y = -3x/2 (Equation 3).
Put Equation 3 in Equation 1:
2x - 3(-3x/2) = 13x - 4(-3x/2).
2x + 4.5x = 13x + 6x.
12.5x = 0.
x = 0.
Put x = 0 in Equation 3:
y = 0.
Q 21)
y = 4x - 1 (Equation 1).
y = -2x - 7 (Equation 2).
Since y = y, therefore:
4x - 1 = -2x - 7.
6x = -6.
x = -1.
Put x = -1 in Equation 1:
y = 4(-1) - 1.
y = -4 - 1.
y = -5.
In short:
Q 19) x = 4; y = 8!!!
Q 20) x = 0 ; y = 0!!!
Q 21) x = -1; y = -5!!!
Answer:
Step-by-step explanation:
Given: In a parallelogram ABCD, diagonals intersect at O and ar(ABCD) is .
We need to find the area of triangle AOB.
We know that each diagonal divide the parallelogram in two equal parts and diagonals bisect each other.
It means both diagonals divide the parallelogram in 4 equal parts.
Hence, the values of ar(AOB) is .
We want to multiply the monomial by the monomial .
Remember that to multiply monomials we need to use the laws of exponents; in this case, the law for multiplying powers with the same base. The rule says that, when you multiply powers of the same base, you just need to add the exponents: , . Also, is worth pointing out that the exponent of a variable with no exponent is 1: .
Remember that we also need to multiply their coefficients , which are the numbers that multiply the variables; again, variables with no numbers have a coefficient of 1, so . Multiply coefficients is easy, you just need to multiply them as you usually do with everyday numbers.
Let's apply all of that to our multiplication:
We can conclude that 2x times x squared is 2x cubed.
Answer:
x =10
Step-by-step explanation:
Using the pythagoras theorem om one of the right triangle;
(√74)² = (x/2)²+7²
74 = (x/2)²+49
(x/2)² = 74 - 49
(x/2)² = 25
Square root both sides
√ (x/2)² = ±√25
x/2 = ±5
x = 2 * ±5
x = ±10
Hence the value of x is 10